Relay apparatus and relaying method for relaying signals

ABSTRACT

This communication device relays a relay signal to be transmitted to and from a first communication device and a second communication device, and is connected to a first apparatus. The communication device transmits the relay signal using a first transmission slot, and also transmits, using a second transmission slot, a signal having been transmitted from the first apparatus, said signal being transmitted within the transmission period of the first transmission slot in a frequency domain different from that of the first transmission slot.

TECHNICAL FIELD

The present invention relates to a communication apparatus and acommunication method.

BACKGROUND ART

A communication method called Multiple-Input Multiple-Out (MIMO), forexample, is a conventional communication method using a plurality ofantennas. Multi-antenna communication represented by MIMO makes itpossible to increase data reception quality and/or increase datacommunication speed (per unit time) by modulating multiple streams oftransmission data, and transmitting modulation signals at the same timefrom different antennas using the same frequency (common frequency).

Further, when multicast communication and/or broadcast communication areperformed in a multi-antenna communication, a transmission apparatussometimes uses a quasi-omni pattern antenna with a substantiallyconstant antenna gain over a wide range of directions in a space. Forexample, Patent Literature (hereinafter, referred to as “PTL”) 1describes that a transmission apparatus transmits modulation signalsusing a quasi-omni pattern antenna.

CITATION LIST Patent Literature

PTL 1

-   WO2011/055536

SUMMARY OF INVENTION

Non-limiting examples of the present disclosure help to provide furtherperformance improvements for communication methods using a plurality ofantennas.

A communication apparatus according to one aspect of the presentdisclosure is a communication apparatus that relays a relay signaltransmitted and received between a first communication apparatus and asecond communication apparatus, and is additionally connected to a firstdevice, in which the communication apparatus transmits the relay signalusing a first transmission slot, and transmits a signal from the firstdevice using a second transmission slot during a transmission period ofthe first transmission slot in a frequency domain different from afrequency domain of the first transmission slot.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, or a storage medium, or any selective combination of a system,an apparatus, a method, an integrated circuit, a computer program, and astorage medium.

Additional benefits and advantages of one aspect of the disclosedembodiments will become apparent from the specification and drawings.The benefits and/or advantages may be individually obtained by thevarious embodiments and features of the specification and drawings,which need not all be provided in order to obtain one or more of suchbenefits and/or advantages.

According to the present disclosure, it is possible to improveperformance in a communication method using a plurality of antennas.

Additional benefits and advantages of one aspect of the disclosedembodiments will become apparent from the specification and drawings.The benefits and/or advantages may be individually obtained by thevarious embodiments and features of the specification and drawings,which need not all be provided in order to obtain one or more of suchbenefits and/or advantages.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an example of a configuration of a base station;

FIG. 2 illustrates an example of a configuration of an antenna sectionof the base station;

FIG. 3 illustrates an example of the configuration of the base station;

FIG. 4 illustrates an example of a configuration of a terminal;

FIG. 5 illustrates an example of a configuration of an antenna sectionof the terminal;

FIG. 6 illustrates an example of the configuration of the terminal;

FIG. 7 illustrates an example of a communication state between the basestation and the terminal;

FIG. 8 illustrates the relationship between multiple streams;

FIG. 9 illustrates an example of a frame configuration;

FIG. 10 illustrates an example of the frame configuration;

FIG. 11 illustrates an example of a symbol configuration;

FIG. 12 illustrates an example of the communication state between thebase station and the terminal;

FIG. 13 illustrates the relationship between a plurality of modulationsignals;

FIG. 14 illustrates an example of the frame configuration;

FIG. 15 illustrates an example of the frame configuration;

FIG. 16 illustrates an example of the symbol configuration;

FIG. 17 illustrates an example of the communication state between thebase station and the terminal;

FIG. 18 illustrates an example of the communication state between thebase station and the terminal;

FIG. 19 illustrates an example of the communication state between thebase station and the terminal;

FIG. 20 illustrates an example of the communication state between thebase station and the terminal;

FIG. 21 illustrates the relationship between a plurality of modulationsignals;

FIG. 22 illustrates an example of the communication state between thebase station and the terminal;

FIG. 23 illustrates a procedure for performing communication between thebase station and the terminal;

FIG. 24 illustrates an example of symbols transmitted by the basestation and the terminal;

FIG. 25 illustrates an example of symbols transmitted by the basestation;

FIG. 26 illustrates an example of the communication state between thebase station and the terminal;

FIG. 27 illustrates an example of symbols transmitted by the basestation;

FIG. 28 illustrates a procedure for performing communication between thebase station and the terminal;

FIG. 29 illustrates an example of the communication state between thebase station and the terminal;

FIG. 30 illustrates a procedure for performing communication between thebase station and the terminal;

FIG. 31 illustrates an example of symbols transmitted by the basestation;

FIG. 32 illustrates an example of symbols transmitted by the basestation;

FIG. 33 illustrates a procedure for performing communication between thebase station and the terminal;

FIG. 34 illustrates a procedure for performing communication between thebase station and the terminal;

FIG. 35 illustrates an example of symbols transmitted by the basestation;

FIG. 36 illustrates a procedure for performing communication between thebase station and the terminal;

FIG. 37 illustrates an example of the configuration of the base station;

FIG. 38 illustrates an example of the frame configuration;

FIG. 39 illustrates an example of the frame configuration;

FIG. 40 illustrates an example of the frame configuration;

FIG. 41 illustrates an example of the frame configuration;

FIG. 42 illustrates an example of allocation of symbol regions toterminals;

FIG. 43 illustrates an example of allocation of symbol regions toterminals;

FIG. 44 illustrates an example of the configuration of the base station;

FIG. 45 illustrates an example of a configuration of a mesh network inwhich repeaters are used;

FIG. 46 illustrates an example of connection between the repeaters;

FIG. 47 illustrates an example of slot allocation;

FIG. 48 illustrates an example of slot allocation;

FIG. 49 illustrates an example of connection between the repeaters;

FIG. 50 illustrates an example of slot allocation;

FIG. 51 illustrates an example of slot allocation;

FIG. 52 illustrates an example of connection between the repeaters;

FIG. 53 illustrates an example of slot allocation;

FIG. 54 illustrates an example of slot allocation;

FIG. 55 illustrates an example of slot allocation;

FIG. 56 illustrates an example of slot allocation; and

FIG. 57 illustrates an example of a configuration of a radio signaltransmitted and received between the repeaters.

DESCRIPTION OF EMBODIMENTS Embodiment 1

FIG. 1 illustrates an example of a configuration of a base station (oran access point or the like) according to the present embodiment.

FIG. 1 illustrates #1 information 101-1, #2 information 101-2, . . . ,and #M information 101-M. That is, #i pieces of information 101-i areillustrated in FIG. 1 . The character “i” is an integer of from 1through M. Note that “M” is an integer equal to or greater than 2. Notethat not all the pieces of information of from the #1 information to the#M information have to be present.

The #1 information 101-1, #2 information 101-2, . . . , and/or #Minformation 101-M and control signal 159 are input to signal processor102. Signal processor 102 performs signal processing based oninformation such as “information on an error correction coding scheme(coding rate, code length (block length)),” “information on a modulationscheme,” “information on precoding,” “a transmission method(multiplexing method),” “whether to perform multicast transmissionand/or to perform unicast transmission (the multicast transmission andthe unicast transmission may also be realized simultaneously),” “thenumber of transmission streams for multicasting,” “a transmission methodin the case of transmission of a multicast modulation signal (which willbe described in detail later),” and/or the like included in controlsignal 159, and outputs signal 103-1 after the signal processing, signal103-2 after the signal processing, . . . , and signal 103-M after thesignal processing (i.e., signals 103-i after the signal processing).Note that, not all the signals of from signal #1 after the signalprocessing to signal #M after the signal processing necessarily have tobe present. At this time, error correction coding is performed on #iinformation 101-i, and mapping according to a configured modulationscheme is then performed. Accordingly, a baseband signal is obtained.Then, signal processor 102 collects baseband signals correspondingrespectively to the pieces of information to perform precoding. Forexample, signal processor 102 may apply Orthogonal Frequency DivisionMultiplexing (OFDM).

Signal 103-1 after the signal processing and control signal 159 areinput to radio 104-1, and the radio performs processing such as bandlimitation, frequency conversion, and amplification on the basis ofcontrol signal 159, and outputs transmission signal 105-1. Then,transmission signal 105-1 is output as a radio wave from antenna section106-1.

Similarly, signal 103-2 after the signal processing and control signal159 are input to radio 104-2, and the radio performs processing such asband limitation, frequency conversion, and amplification on the basis ofcontrol signal 159, and outputs transmission signal 105-2. Then,transmission signal 105-2 is output as a radio wave from antenna section106-2. Descriptions of radios 104-3 to 104-(M−1) are omitted.

Signal 103-M after the signal processing and control signal 159 areinput to radio 104-M, and the radio performs processing such as bandlimitation, frequency conversion, and amplification on the basis ofcontrol signal 159, and outputs transmission signal 105-M. Then,transmission signal 105-M is output as a radio wave from antenna section106-M.

When there is no signal after signal processing, the radios do not needto perform the above processing.

Reception signal group 152 received by reception-antenna group 151 isinput to radio group 153, and the radio group performs processing suchas frequency conversion on the reception signal group and outputsbaseband-signal group 154.

Baseband-signal group 154 is input to signal processor 155, and thesignal processor performs demodulation and error correction decoding. Inother words, signal processor 155 also performs processing such as timesynchronization, frequency synchronization, and channel estimation.Since signal processor 155 receives a modulation signal transmitted byone or more terminals at this time for performing the processing, thesignal processor obtains data transmitted by each of the terminals andcontrol information transmitted by each of the terminals. Accordingly,signal processor 155 outputs data group 156 corresponding to one or moreterminals and control information group 157 corresponding to one or moreterminals.

Control information group 157 and configuration signal 160 are input tosetter 158, and the setter determines, based on control informationgroup 157, the “error correction coding scheme (coding rate and codelength (block length)),” “modulation scheme,” “precoding method,”“transmission method,” “antenna configuration,” “whether to performmulticast transmission and/or to perform unicast transmission (themulticast transmission and the unicast transmission may be realizedsimultaneously),” “number of transmission streams for multicasting,”“transmission method for transmitting a multicast modulation signal,”and/or the like to output control signal 159 including the determinedinformation.

Control signal 159 is input to antenna sections 106-1, 106-2, . . . ,and/or 106-M. An operation at this time will be described with referenceto FIG. 2 .

FIG. 2 illustrates an example of the configuration of each of antennasections 106-1, 106-2, . . . , and 106-M. Each of the antenna sectionsincludes a plurality of antennas as illustrated in FIG. 2 . Note that,while FIG. 2 illustrates four antennas, each of the antenna sectionsonly has to include a plurality of antennas. Note that the number ofantennas is not limited to 4.

FIG. 2 is a configuration of antenna section 106-i. The character “i” isan integer of from 1 through M.

Transmission signals 201 (corresponding to transmission signals 105-i inFIG. 1 ) are input to distributor 202, and the distributor distributestransmission signals 201 to output signals 203-1, 203-2, 203-3, and/or203-4.

Signal 203-1 and control signal 200 (corresponding to control signal 159in FIG. 1 ) are input to multiplier 204-1, and the multiplier multipliessignal 203-1 by factor W1 based on information on a multiplicationfactor included in control signal 200, to output signal 205-1 resultingfrom multiplication. Factor W1 is defined by a complex number and, thus,W1 may be a real number. Accordingly, when signal 203-1 is expressed asv1(t), signal 205-1 resulting from multiplication can be expressed asW1×v1(t) (t denotes time). Signal 205-1 resulting from multiplication isoutput as a radio wave from antenna 206-1.

Similarly, signal 203-2 and control signal 200 are input to multiplier204-2, and the multiplier multiplies signal 203-2 by factor W2 based onthe information on the multiplication factor included in control signal200, to output signal 205-2 resulting from multiplication. Factor W2 isdefined by a complex number and, thus, W2 can be a real number.Accordingly, when signal 203-2 is expressed as v2(t), signal 205-2resulting from multiplication can be expressed as W2×v2(t) (t denotestime). Signal 205-2 resulting from multiplication is output as a radiowave from antenna 206-2.

Signal 203-3 and control signal 200 are input to multiplier 204-3, andthe multiplier multiplies signal 203-3 by factor W3 based on theinformation on the multiplication factor included in control signal 200,to output signal 205-3 resulting from multiplication. Factor W3 isdefined by a complex number and, thus, W3 can be a real number.Accordingly, when signal 203-3 is expressed as v3(t), signal 205-3resulting from multiplication can be expressed as W3×v3(t) (t denotestime). Signal 205-3 resulting from multiplication is output as a radiowave from antenna 206-3.

Signal 203-4 and control signal 200 are input to multiplier 204-4, andthe multiplier multiplies signal 203-4 by factor W4 based on theinformation on the multiplication factor included in control signal 200,to output signal 205-4 resulting from multiplication. Factor W4 isdefined by a complex number and, thus, W4 can be a real number.Accordingly, when signal 203-4 is expressed as v4(t), signal 205-4resulting from multiplication can be expressed as W4×v4(t) (t denotestime). Signal 205-4 resulting from multiplication is output as a radiowave from antenna 206-4.

Note that, at least two of the absolute value of W1, the absolute valueof W2, the absolute value of W3, and the absolute value of W4 may beequal to each other.

FIG. 3 illustrates a configuration of the base station in the presentembodiment, which is different from the configuration of the basestation in FIG. 1 . Components in FIG. 3 that operate in the same manneras those in FIG. 1 are provided with the same reference numerals, andthe descriptions of those components are omitted below.

Modulation signal 105-1, modulation signal 105-2, . . . , and/ormodulation signal 105-M and control signal 159 are input to weightingcombiner 301. Weighting combiner 301 performs weighted combination onmodulation signal 105-1, modulation signal 105-2, . . . , and/ormodulation signal 105-M based on information relevant to weightedcombination included in control signal 159, to output signals 302-1,302-2, . . . , and/or 302-K resulting from the weighted combination. Thecharacter “K” is an integer equal to or greater than 1. Signal 302-1resulting from the weighted combination is output as a radio wave fromantenna 303-1, signal 302-2 resulting from the weighted combination isoutput as a radio wave from antenna 303-2, . . . , and signal 302-Kresulting from the weighted combination is output as a radio wave fromantenna 303-K.

Signal y_(i)(t) 302-i resulting from the weighted combination, where iis an integer of from 1 through K, is expressed as follows (t denotestime).

$\begin{matrix}\lbrack 1\rbrack &  \\\begin{matrix}{{y_{i}(t)} = {{A_{i1} \times {x_{1}(t)}} + {A_{i2} \times {x_{2}(t)}} + \ldots + {A_{iM} \times {x_{M}(t)}}}} \\{= {\sum\limits_{j = 1}^{M}{A_{ij} \times {x_{j}(t)}}}}\end{matrix} & \left( {{Equation}1} \right)\end{matrix}$

In Equation 1, A_(ij) is defined as a complex number and, thus, A_(ij)can be a real number. Correspondigly, x_(j)(t) is modulation signal105-j. The character “j” is an integer of from 1 through M.

FIG. 4 illustrates an example of a configuration of a terminal. Controlsignal 410 is input to antenna sections 401-1, 401-2, . . . , and/or401-N. N is an integer equal to or greater than 1.

Reception signal 402-1 received by antenna section 401-1 and controlsignal 410 are input to radio 403-1, and the radio performs processingsuch as frequency conversion and the like on reception signal 402-1based on control signal 410, to output baseband signal 404-1.

Similarly, reception signal 402-2 received by antenna section 401-2 andcontrol signal 410 are input to radio 403-2, and the radio performsprocessing such as frequency conversion and the like on reception signal402-2 based on control signal 410, to output baseband signal 404-2. Notethat, descriptions of radios 403-3 to 403-(N−1) are omitted.

Reception signal 402-N received by antenna section 401-N and controlsignal 410 are input to radio 403-N, and the radio performs processingsuch as frequency conversion and the like on reception signal 402-Nbased on control signal 410, to output baseband signal 404-N.

However, not all of radios 403-1, 403-2, . . . , and 403-N necessarilyoperate. Correspondingly, not all of baseband signals 404-1, 404-2, . .. , and 404-N are necessarily present.

Baseband signals 404-1, 404-2, . . . , and 404-N and control signal 410are input to signal processor 405, and the signal processor performsprocessing of demodulation and error correction decoding based oncontrol signal 410, to output data 406, transmission control information407, and control information 408. In other words, signal processor 405also performs processing such as time synchronization, frequencysynchronization, and channel estimation.

Control information 408 is input to setter 409, and the setter performssetting for a reception method and outputs control signal 410.

Information 451 and transmission control information 407 are input tosignal processor 452, and the signal processor performs processing suchas error correction encoding and mapping according to a configuredmodulation scheme, to output baseband-signal group 453.

Baseband-signal group 453 is input to radio group 454, and the radiogroup performs processing such as band limitation, frequency conversion,and amplification, to output transmission-signal group 455.Transmission-signal group 455 is output from transmission-antenna group456 as a radio wave.

FIG. 5 illustrates an example of the configuration of each of antennasections 401-1, 401-2, . . . , and 401-N. Each of the antenna sectionsincludes a plurality of antennas as illustrated in FIG. 5 . Note that,while FIG. 5 illustrates four antennas, each of the antenna sectionsonly has to include a plurality of antennas. Note that, the number ofantennas of the antenna section is not limited to 4.

FIG. 5 illustrates the configuration of antenna section 401-i. Thecharacter “i” is an integer of from 1 through N.

Reception signal 502-1 received by antenna 501-1 and control signal 500(corresponding to control signal 410 in FIG. 4 ) are input to multiplier503-1, and the multiplier multiplies reception signal 502-1 by factor D1based on the information on the multiplication factor included incontrol signal 500, to output signal 504-1 resulting frommultiplication. Factor D1 is defined by a complex number and, thus, D1may be a real number. Accordingly, when reception signal 502-1 isexpressed as e1(t), signal 504-1 resulting from multiplication can beexpressed as D1×e1(t) (t denotes time).

Similarly, reception signal 502-2 received by antenna 501-2 and controlsignal 500 are input to multiplier 503-2, and the multiplier multipliesreception signal 502-2 by factor D2 based on the information on themultiplication factor included in control signal 500, to output signal504-2 resulting from multiplication. Factor D2 is defined by a complexnumber and, thus, D2 may be a real number. Accordingly, when receptionsignal 502-2 is expressed as e2(t), signal 504-2 resulting frommultiplication can be expressed as D2×e2(t) (t denotes time).

Similarly, reception signal 502-3 received by antenna 501-3 and controlsignal 500 are input to multiplier 503-3, and the multiplier multipliesreception signal 502-3 by factor D3 based on the information on themultiplication factor included in control signal 500, to output signal504-3 resulting from multiplication. Factor D3 is defined by a complexnumber and, thus, D3 may be a real number. Accordingly, when receptionsignal 502-3 is expressed as e3(t), signal 504-3 resulting frommultiplication can be expressed as D3×e3(t) (t denotes time).

Reception signal 502-4 received by antenna 501-4 and control signal 500are input to multiplier 503-4, and the multiplier multiplies receptionsignal 502-4 by factor D4 based on the information on the multiplicationfactor included in control signal 500, to output signal 504-4 resultingfrom multiplication. Factor D4 is defined by a complex number and, thus,D4 may be a real number. Accordingly, when reception signal 502-4 isexpressed as e4(t), signal 504-4 resulting from multiplication can beexpressed as D4×e4(t) (t denotes time).

Signals 504-1, 504-2, 504-3, and 504-4 resulting from multiplication areinput to combiner 505, and the combiner adds together signals 504-1,504-2, 504-3, and 504-4 resulting from multiplication to output combinedsignal 506 (corresponding to reception signal 402-i in FIG. 4 ).Accordingly, combined signal 506 is expressed asD1×e1(t)+D2×e2(t)+D3×e3(t)+D4×e4(t).

FIG. 6 illustrates a configuration of a terminal in the presentembodiment, which is different from the configuration of the terminal inFIG. 4 . Components in FIG. 6 that operate in the same manner as thosein FIG. 4 are provided with the same reference numerals, and thedescriptions of those components are omitted below.

Reception signal 602-1 received by antenna 601-1 and control signal 410are input to multiplier 603-1, and the multiplier multiplies receptionsignal 602-1 by factor G1 based on information on a multiplicationfactor included in control signal 410, to output signal 604-1 resultingfrom multiplication. Factor G1 is defined by a complex number and, thus,G1 may be a real number. Accordingly, when reception signal 602-1 isexpressed as c1(t), signal 604-1 resulting from multiplication can beexpressed as G1×c1(t) (t denotes time).

Similarly, reception signal 602-2 received by antenna 601-2 and controlsignal 410 are input to multiplier 603-2, and the multiplier multipliesreception signal 602-2 by factor G2 based on the information on themultiplication factor included in control signal 410, to output signal604-2 resulting from multiplication. Factor G2 is defined by a complexnumber and, thus, G2 may be a real number. Accordingly, when receptionsignal 602-2 is expressed as c2(t), signal 604-2 resulting frommultiplication can be expressed as G2×c2(t) (t denotes time). Thedescriptions of multipliers 603-3 to 603-(L−1) are omitted.

Reception signal 602-L received by antenna 601-L and control signal 410are input to multiplier 603-L, and the multiplier multiplies receptionsignal 602-L by factor GL based on the information on the multiplicationfactor included in control signal 410, to output signal 604-L resultingfrom multiplication. Factor GL is defined by a complex number and, thus,GL may be a real number. Accordingly, when reception signal 602-L isexpressed as cL(t), signal 604-L resulting from multiplication can beexpressed as GL×cL(t) (t denotes time).

Thus, reception signal 602-i received by antenna 601-i and controlsignal 410 are input to multiplier 603-i, and the multiplier multipliesreception signal 602-i by factor Gi based on the information on themultiplication factor included in control signal 410, to output signal604-i resulting from multiplication. Factor Gi is defined by a complexnumber and, thus, Gi may be a real number. Accordingly, when receptionsignal 602-i is expressed as ci(t), signal 604-i resulting frommultiplication can be expressed as Gi×ci(t) (t denotes time). Note that,“i” is an integer of from 1 through L, and L is an integer equal to orgreater than 2.

Signal 604-1 resulting from multiplication, signal 604-2 resulting frommultiplication, . . . , and/or signal 604-L resulting frommultiplication and control signal 410 are input to processor 605, andthe processor performs signal processing based on control signal 410, tooutput processed signals 606-1, 606-2, . . . , and/or 606-N. N is aninteger equal to or greater than 2. In this case, signal 604-i resultingfrom multiplication is expressed as p_(i)(t). The character “i” is aninteger of from 1 through L. In this case, processed signal 606-j(r_(j)(t)) is expressed as follows (where j is an integer of from 1through N).

$\begin{matrix}\begin{matrix}\lbrack 2\rbrack &  \\\begin{matrix}{{r_{j}(t)} = {{B_{j1} \times {p}_{1}(t)} + {{B}_{j2} \times {p_{2}(t)}} + \ldots + {B_{jL} \times {p_{L}(t)}}}} \\{= {\sum\limits_{i = 1}^{L}{B_{ji} \times {p}_{i}(t)}}}\end{matrix} & \left( {{Equation}2} \right)\end{matrix} & \end{matrix}$

In Equation 2, B_(ji) is defined by a complex number and, thus, B_(ji)may be a real number.

FIG. 7 illustrates an example of a communication state between the basestation and the terminal. Note that, the base station may also bereferred to as an access point, broadcasting station, or the like.

Base station 700 includes a plurality of antennas, and transmits aplurality of transmission signals from transmission antenna 701. Basestation 700 is configured, for example, as in FIG. 1 or 3 and performs,at signal processor 102 (and/or at weighting combiner 301), precoding(weighted combination) to perform transmission beamforming (directivitycontrol).

FIG. 7 illustrates transmission beam 702-1 for transmitting data ofstream 1, transmission beam 702-2 for transmitting data of stream 1, andtransmission beam 702-3 for transmitting data of stream 1. FIG. 7 alsoillustrates transmission beam 703-1 for transmitting data of stream 2,transmission beam 703-2 for transmitting data of stream 2, andtransmission beam 703-3 for transmitting data of stream 2.

Note that, while the number of transmission beams for transmitting dataof stream 1 is 3 and the number of transmission beams for transmittingdata of stream 2 is 3 in FIG. 7 , the number of transmission beams isnot limited to this example. That is, there only have to be a pluralityof transmission beams for transmitting data of stream 1 and a pluralityof transmission beams for transmitting data of stream 2.

FIG. 7 includes terminals 704-1, 704-2, 704-3, 704-4, and 704-5. Theseterminals may be configured as illustrated in FIG. 4 or 5 , for example.

For example, terminal 704-1 performs directivity control performed forreception (hereinafter, referred to as “reception directivity control”)at “signal processor 405,” “antennas 401-1 to 401-N,” and/or“multipliers 603-1 to 603-L and processor 605” to form receptiondirectivity 705-1 and reception directivity 706-1. Reception directivity705-1 allows terminal 704-1 to receive and demodulate transmission beam702-1 for transmitting data of stream 1, and reception directivity 706-1allows terminal 704-1 to receive and demodulate transmission beam 703-1for transmitting data of stream 2.

Similarly, terminal 704-2 performs the reception directivity control at“signal processor 405,” “antennas 401-1 to 401-N,” and/or “multipliers603-1 to 603-L and processor 605” to form reception directivity 705-2and reception directivity 706-2. Reception directivity 705-2 allowsterminal 704-2 to receive and demodulate transmission beam 702-1 fortransmitting data of stream 1, and reception directivity 706-2 allowsterminal 704-2 to receive and demodulate transmission beam 703-1 fortransmitting data of stream 2.

Terminal 704-3 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and processor 605” to form reception directivity 705-3 andreception directivity 706-3. Reception directivity 705-3 allows terminal704-3 to receive and demodulate transmission beam 702-2 for transmittingdata of stream 1, and reception directivity 706-3 allows terminal 704-3to receive and demodulate transmission beam 703-2 for transmitting dataof stream 2.

Terminal 704-4 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and processor 605” to form reception directivity 705-4 andreception directivity 706-4. Reception directivity 705-4 allows terminal704-4 to receive and demodulate transmission beam 702-3 for transmittingdata of stream 1, and reception directivity 706-4 allows terminal 704-4to receive and demodulate transmission beam 703-2 for transmitting dataof stream 2.

Terminal 704-5 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and processor 605” to form reception directivity 705-5 andreception directivity 706-5. Reception directivity 705-5 allows terminal704-5 to receive and demodulate transmission beam 702-3 for transmittingdata of stream 1, and reception directivity 706-5 allows terminal 704-5to receive and demodulate transmission beam 703-3 for transmitting dataof stream 2.

In FIG. 7 , each of the terminals can obtain the data of stream 1 withhigh quality by selecting, depending on its spatial position, at leastone transmission beam of transmission beams 702-1, 702-2, and 702-3 fortransmitting the data of stream 1 and by directing the receptiondirectivity. Each of the terminals also can obtain the data of stream 2with high quality by selecting, depending on its spatial position, atleast one transmission beam of transmission beams 703-1, 703-2, and703-3 for transmitting the data of stream 2 and by directing thereception directivity.

Base station 700 transmits transmission beam 702-1 for transmitting thedata of stream 1 and transmission beam 703-1 for transmitting the dataof stream 2 using the same frequency (the same frequency band) and thesame time. Base station 700 transmits transmission beam 702-2 fortransmitting the data of stream 1 and transmission beam 703-2 fortransmitting the data of stream 2 using the same frequency (the samefrequency band) and the same time. Base station 700 transmitstransmission beam 702-3 for transmitting the data of stream 1 andtransmission beam 703-3 for transmitting the data of stream 2 using thesame frequency (the same frequency band) and the same time.

Note that, transmission beams 702-1, 702-2, and 702-3 for transmittingthe data of stream 1 may be beams of the same frequency (the samefrequency band) or beams of frequencies (frequency bands) different fromone another. Transmission beams 703-1, 703-2, and 703-3 for transmittingthe data of stream 2 may be beams of the same frequency (the samefrequency band) or beams of frequencies (frequency bands) different fromone another.

The operation of setter 158 of the base station illustrated in FIG. 1 or3 for the above case will be described.

Configuration signal 160 is input to setter 158. Configuration signal160 includes information indicating “whether to perform multicasttransmission and/or to perform unicast transmission.” When the basestation performs transmission as illustrated in FIG. 7 , configurationsignal 160 provides input of the information “multicast transmission isto be performed” into setter 158.

Configuration signal 160 includes information indicating the “number oftransmission streams for multicasting.” When the base station performstransmission as illustrated in FIG. 7 , configuration signal 160provides input of the information “the number of transmission streams is2” into setter 158.

Configuration signal 160 may include information indicating “how manytransmission beams are used to transmit each stream.” When the basestation performs transmission as illustrated in FIG. 7 , configurationsignal 160 provides input of the information “the number of transmissionbeams for transmitting stream 1 is 3 and the number of transmissionbeams for transmitting stream 2 is 3” into setter 158.

The base station of FIG. 1 or 3 may transmit a control informationsymbol including information indicating whether data symbols are“multicast transmission and/or unicast transmission,” informationindicating “the number of transmission streams for multicasting,” and/orinformation indicating “how many transmission beams are used to transmiteach stream,” and the like. It is thus possible for the terminal toperform suitable reception. Details of the configuration of the controlinformation symbol will be described later.

FIG. 8 explains the relationship between #i information 101-i in FIG. 1or 3 and the “stream 1” and “stream 2” described with reference to FIG.7 .

For example, processing such as error correction coding is performed on#1 information 101-1 to obtain data after the error correction coding.This data after the error correction coding is called “#1 transmissiondata.” Then, mapping is performed on the #1 transmission data to obtaindata symbols. Then, the data symbols are distributed to stream 1 andstream 2 to obtain data symbols (data symbol group) of stream 1 and datasymbols (data symbol group) of stream 2. The symbol group of stream 1includes data symbols (data symbol group) of stream 1, and the symbolgroup of stream 1 is transmitted from the base station of FIG. 1 or 3 .The symbol group of stream 2 includes data symbols (data symbol group)of stream 2, and the symbol group of stream 2 is transmitted from thebase station of FIG. 1 or 3 .

FIG. 9 illustrates an example of a frame configuration in which thehorizontal axis represents time.

The #1 symbol group 901-1 of stream 1 in FIG. 9 is a symbol group oftransmission beam 702-1 for transmitting data of stream 1 in FIG. 7 .

The #2 symbol group 901-2 of stream 1 in FIG. 9 is a symbol group oftransmission beam 702-2 for transmitting data of stream 1 in FIG. 7 .

The #3 symbol group 901-3 of stream 1 in FIG. 9 is a symbol group oftransmission beam 702-3 for transmitting data of stream 1 in FIG. 7 .

The #1 symbol group 902-1 of stream 2 in FIG. 9 is a symbol group oftransmission beam 703-1 for transmitting data of stream 2 in FIG. 7 .

The #2 symbol group 902-2 of stream 2 in FIG. 9 is a symbol group oftransmission beam 703-2 for transmitting data of stream 2 in FIG. 7 .

The #3 symbol group 902-3 of stream 2 in FIG. 9 is a symbol group oftransmission beam 703-3 for transmitting data of stream 2 in FIG. 7 .

The #1 symbol group 901-1 of stream 1, #2 symbol group 901-2 of stream1, #3 symbol group 901-3 of stream 1, #1 symbol group 902-1 of stream 2,#2 symbol group 902-2 of stream 2, and #3 symbol group 902-3 of stream 2exist, for example, in time section 1.

As described above, #1 symbol group 901-1 of stream 1 and #2 symbolgroup 902-1 of stream 2 are transmitted using the same frequency (thesame frequency band). The #2 symbol group 901-2 of stream 1 and #2symbol group 902-2 of stream 2 are transmitted using the same frequency(the same frequency band). The #3 symbol group 901-3 of stream 1 and #3symbol group 902-3 of stream 2 are transmitted using the same frequency(the same frequency band).

For example, in accordance with the procedure of FIG. 8 , “data symbolgroup A of stream 1” and “data symbol group A of stream 2” are generatedfrom the information. Then, “data symbol group A-1 of stream 1” composedof the same symbols as the symbols constituting “data symbol group A ofstream 1” is prepared. A “data symbol group A-2 of stream 1” composed ofthe same symbols as the symbols constituting “data symbol group A ofstream 1” is prepared. A “data symbol group A-3 of stream 1” composed ofthe same symbols as the symbols constituting “data symbol group A ofstream 1” is prepared.

That is, the symbols constituting “data symbol group A-1 of stream 1,”the symbols constituting “data symbol group A-2 of stream 1,” and thesymbols constituting “data symbol group A-3 of stream 1” are the same.

In this case, #1 symbol group 901-1 of stream 1 in FIG. 9 includes “datasymbol group A-1 of stream 1.” The #2 symbol group 901-2 of stream 1 inFIG. 9 includes “data symbol group A-2 of stream 1.” The #3 symbol group901-3 of stream 1 in FIG. 9 includes “data symbol group A-3 of stream1.” That is, #1 symbol group 901-1 of stream 1, #2 symbol group 901-2 ofstream 1, and #3 symbol group 901-3 of stream 1 include the same datasymbol group.

Further, “data symbol group A-1 of stream 2” composed of the samesymbols as the symbols constituting “data symbol group A of stream 2” isprepared. A “data symbol group A-2 of stream 2” composed of the samesymbols as the symbols constituting “data symbol group A of stream 2” isprepared. A “data symbol group A-3 of stream 2” composed of the samesymbols as the symbols constituting “data symbol group A of stream 2” isprepared.

That is, the symbols constituting “data symbol group A-1 of stream 2,”the symbols constituting “data symbol group A-2 of stream 2,” and thesymbols constituting “data symbol group A-3 of stream 2” are the same.

In this case, #1 symbol group 902-1 of stream 2 in FIG. 9 includes “datasymbol group A-1 of stream 2,” #2 symbol group 902-2 of stream 2 in FIG.9 includes “data symbol group A-2 of stream 2,” and #3 symbol group902-3 of stream 2 in FIG. 9 includes “data symbol group A-3 of stream2.” That is, #1 symbol group 902-1 of stream 2, #2 symbol group 902-2 ofstream 2, and #3 symbol group 902-3 of stream 2 include the same datasymbol group.

FIG. 10 illustrates an example of the frame configuration of “symbolgroup #Y of stream X” (X=1 or 2; Y=1, 2, or 3) described in FIG. 9 . InFIG. 10 , the horizontal axis indicates the time direction, and controlinformation symbol 1001 and data symbol group 1002 of the stream arearranged in the time direction. In this case, data symbol group 1002 ofthe stream is symbols for transmitting “data symbol group A of stream 1”or “data symbol group A of stream 2” described with reference to FIG. 9.

Note that, a multi-carrier system such as an Orthogonal FrequencyDivision Multiplexing (OFDM) scheme may be used for the frameconfiguration in FIG. 10 , and in this case, symbols may be present inthe frequency-axis direction. In addition, each of the symbols mayinclude a reference symbol for a reception apparatus to perform time andfrequency synchronization, a reference symbol for the receptionapparatus to detect a signal, a reference symbol for the receptionapparatus to perform channel estimation, and/or the like. The frameconfiguration is not limited to that illustrated in FIG. 10 , andcontrol information symbol 1001 and data symbol group 1002 of a streammay also be arranged in any manner. Note that, the reference symbol mayalso be referred to as a preamble or a pilot symbol.

Next, the configuration of control information symbol 1001 will bedescribed.

FIG. 11 illustrates an example of a configuration of a symbol to betransmitted as the control information symbol in FIG. 10 . In FIG. 11 ,the horizontal axis represents time. In FIG. 11 , the terminal receives“training symbol 1101 for a terminal to perform reception directivitycontrol” to determine a signal processing method for receptiondirectivity control performed at “signal processor 405,” “antennas 401-1to 401-N,” and/or “multipliers 603-1 to 603-L and processor 605.”

The terminal receives “symbol 1102 for indicating the number oftransmission streams used when multicast is being performed,” so as tobe able to know the number of streams to be obtained.

The terminal receives “symbol 1103 for indicating which stream of datasymbols the data symbols of the stream is,” so as to be able to knowwhich one of the streams being transmitted by the base station has beensuccessfully received.

An example of the above will be described.

A description will be given of such a case as illustrated in FIG. 7where the base station transmits transmission beams of streams. Further,a description will be given of specific information of the controlinformation symbol in #1 symbol group 901-1 of stream 1 in FIG. 9 .

Since the base station transmits “stream 1” and “stream 2” in the caseof FIG. 7 , the information of “symbol 1102 for indicating the number oftransmission streams used when multicast is being performed” is “2.”

Further, since #1 symbol group 901-1 of stream 1 in FIG. 9 sends thedata symbols of stream 1, the information of “symbol 1103 for indicatingwhich stream of data symbols the data symbols of the stream is” is“stream 1.”

A description will be given, for example, of a case where the terminalreceives #1 symbol group 901-1 of stream 1 in FIG. 9 . At this time, theterminal recognizes, from “symbol 1102 for indicating the number oftransmission streams used when multicast is being performed,” that theinformation “the number of transmission streams is 2” has been obtained,and, from “symbol 1103 for indicating which stream of data symbols thedata symbol group is,” that the information “data symbols of stream 1”has been obtained.

Then, since the terminal recognizes that “the number of transmissionstreams is 2” and the obtained data symbols are the “data symbols ofstream 1,” the terminal recognizes that “data symbols of stream 2” areto be obtained. Thus, the terminal can begin operation of searching forsymbols of stream 2. For example, the terminal searches for thetransmission beam of any of #1 symbol group 902-1 of stream 2, #2 symbolgroup 902-2 of stream 2, and #3 symbol group 902-3 of stream 2 in FIG. 9.

Then, the terminal obtains the transmission beam of any of #1 symbolgroup 902-1 of stream 2, #2 symbol group 902-2 of stream 2, and #3symbol group 902-3 of stream 2, to obtain the data symbols of both thedata symbols of stream 1 and the data symbols of stream 2.

As an effect of the present embodiment, the control information symbolconfigured as described above allows the terminal to accurately obtaindata symbols.

As described above, in the multicast data transmission and the broadcastdata transmission, the base station transmits data symbols using aplurality of transmission beams, and the terminal selectively receives ahigh-quality beam out of a plurality of transmission beams. Thetransmission directivity control and the reception directivity controlare performed on the modulation signal transmitted by the base station,so that, as an effect of the present embodiment, it is possible to widenan area where high data reception quality is achieved.

Note that, although the terminal performs the reception directivitycontrol in the above description, the aforementioned effects can beobtained even when the terminal does not perform the receptiondirectivity control.

Note also that, the modulation scheme for “data symbol group 1002 of thestream” in FIG. 10 may be any modulation scheme. Note also that, themapping method of the modulation scheme for “data symbol group 1002 ofthe stream” may be switched for each symbol. That is, the phase of aconstellation may be switched for each symbol on the in-phaseI-quadrature Q plane after mapping.

FIG. 12 is an example of the communication state between the basestation and the terminal, which is different from the example in FIG. 7. Note that, components in FIG. 12 that operate in the same manner asthose in FIG. 7 are provided with the same reference numerals.

Base station 700 includes a plurality of antennas and transmits aplurality of transmission signals from transmission antenna 701. Basestation 700 is configured, for example, as illustrated in FIG. 1 or 3and performs, at signal processor 102 (and/or at weighting combiner301), precoding (weighted combination) to perform transmissionbeamforming (directivity control).

FIG. 12 illustrates transmission beam 1202-1 for transmitting“modulation signal 1,” transmission beam 1202-2 for transmitting“modulation signal 1,” and transmission beam 1202-3 for transmitting“modulation signal 1.” FIG. 12 also illustrates transmission beam 1203-1for transmitting “modulation signal 2,” transmission beam 1203-2 fortransmitting “modulation signal 2,” and transmission beam 1203-3 fortransmitting “modulation signal 2.”

While the number of transmission beams for transmitting “modulationsignal 1” is 3 and the number of transmission beams for transmitting“modulation signal 2” is 3 in FIG. 12 , the number of transmission beamsis not limited thereto. That is, there only have to be a plurality oftransmission beams for transmitting “modulation signal 1” and aplurality of transmission beams for transmitting “modulation signal 2.”Note that, modulation signal 1 and modulation signal 2 will be describedin detail later.

FIG. 12 includes terminals 704-1, 704-2, 704-3, 704-4, and 704-5. Theseterminals may be configured as illustrated in FIGS. 4 and 5 , forexample.

For example, terminal 704-1 performs reception directivity control at“signal processor 405,” “antennas 401-1 to 401-N,” and/or “multipliers603-1 to 603-L and the processor 605” to form reception directivity705-1 and reception directivity 706-1. Reception directivity 705-1allows terminal 704-1 to receive and demodulate transmission beam 1202-1for transmitting “modulation signal 1,” and reception directivity 706-1allows terminal 704-1 to receive and demodulate transmission beam 1203-1for transmitting “modulation signal 2.”

Similarly, terminal 704-2 performs the reception directivity control at“signal processor 405,” “antennas 401-1 to 401-N,” and/or “multipliers603-1 to 603-L and the processor 605” to form reception directivity705-2 and reception directivity 706-2. Reception directivity 705-2allows terminal 704-2 to receive and demodulate transmission beam 1202-1for transmitting “modulation signal 1,” and reception directivity 706-2allows terminal 704-2 to receive and demodulate transmission beam 1203-1for transmitting “modulation signal 2.”

Terminal 704-3 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and the processor 605” to form reception directivity 705-3 andreception directivity 706-3. Reception directivity 705-3 allows terminal704-3 to receive and demodulate transmission beam 1202-2 fortransmitting “modulation signal 1,” and reception directivity 706-3allows terminal 704-3 to receive and demodulate transmission beam 1203-2for transmitting “modulation signal 2.”

Terminal 704-4 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and the processor 605” to form reception directivity 705-4 andreception directivity 706-4. Reception directivity 705-4 allows terminal704-4 to receive and demodulate transmission beam 1202-3 fortransmitting “modulation signal 1,” and reception directivity 706-4allows terminal 704-4 to receive and demodulate transmission beam 1203-2for transmitting “modulation signal 2.”

Terminal 704-5 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and the processor 605” to form reception directivity 705-5 andreception directivity 706-5. Reception directivity 705-5 allows terminal704-5 to receive and demodulate transmission beam 1202-3 fortransmitting “modulation signal 1,” and reception directivity 706-5allows terminal 704-5 to receive and demodulate transmission beam 1203-3for transmitting “modulation signal 2.”

In FIG. 12 , each of the terminals can obtain “modulation signal 1” withhigh quality by selecting, depending on its spatial position, at leastone transmission beam of transmission beams 1202-1, 1202-2, and 1202-3for transmitting “modulation signal 1” and by directing the receptiondirectivity. Each of the terminals also can obtain “modulation signal 2”with high quality by selecting, depending on its spatial position, atleast one transmission beam of transmission beams 1203-1, 1203-2, and1203-3 for transmitting “modulation signal 2” and by directing thereception directivity.

Base station 700 transmits transmission beam 1202-1 for transmitting“modulation signal 1” and transmission beam 1203-1 for transmitting“modulation signal 2” using the same frequency (the same frequency band)and the same time. Base station 700 transmits transmission beam 1202-2for transmitting “modulation signal 1” and transmission beam 1203-2 fortransmitting “modulation signal 2” using the same frequency (the samefrequency band) and the same time. Base station 700 transmitstransmission beam 1202-3 for transmitting “modulation signal 1” andtransmission beam 1203-3 for transmitting “modulation signal 2” usingthe same frequency (the same frequency band) and the same time.

Transmission beams 1202-1, 1202-2, and 1202-3 for transmitting“modulation signal 1” may be beams of the same frequency (the samefrequency band) or may be beams of frequencies (frequency bands)different from one another. Transmission beams 1203-1, 1203-2, and1203-3 for transmitting “modulation signal 2” may be beams of the samefrequency (the same frequency band) or may be beams of frequencies(frequency bands) different from one another.

The operation of setter 158 of the base station illustrated in FIG. 1 or3 for the above case will be described.

Configuration signal 160 is input to setter 158. Configuration signal160 includes information indicating “whether to perform multicasttransmission and/or to perform unicast transmission.” When the basestation performs transmission as illustrated in FIG. 12 , configurationsignal 160 provides input of the information “multicast transmission isto be performed” into setter 158.

Configuration signal 160 includes information indicating “the number oftransmission modulation signals for multicasting.” When the base stationperforms transmission as illustrated in FIG. 12 , configuration signal160 provides input of the information “the number of the transmissionmodulation signals is 2” into setter 158.

Configuration signal 160 may include information indicating “how manytransmission beams are used to transmit each modulation signal.” Whenthe base station performs transmission as illustrated in FIG. 12 ,configuration signal 160 provides input of the information “the numberof transmission beams for transmitting modulation signal 1 is 3 and thenumber of transmission beams for transmitting modulation signal 2 is 3”into setter 158.

The base station of FIG. 1 or 3 may transmit a control informationsymbol including information indicating whether data symbols are“multicast transmission and/or unicast transmission,” informationindicating “the number of transmission modulation signals formulticasting,” and/or information indicating “how many transmissionbeams are used to transmit each modulation signal,” and the like. It isthus possible for the terminal to perform suitable reception. Details ofthe configuration of the control information symbol will be describedlater.

FIG. 13 explains the relationship between #i information 101-i in FIG. 1or 3 and “modulation signal 1” and “modulation signal 2” described withreference to FIG. 12 .

For example, processing such as error correction coding is performed on#1 information 101-1 to obtain data after the error correction coding.This data after the error correction coding is called “#1 transmissiondata.” Then, mapping is performed on the #1 transmission data to obtaindata symbols. Then, the data symbols are distributed to stream 1 andstream 2 to obtain data symbols (data symbol group) of stream 1 and datasymbols (data symbol group) of stream 2. One of the data symbols ofstream 1 having symbol number i is expressed as s1(i), and one of thedata symbols of stream 2 having symbol number i is expressed as s2(i).In this case, “modulation signal 1” tx1(i) with symbol number i isexpressed, for example, as follows.[3]tx1(i)=α(i)×s1(i)+β(i)×s2(i)  (Equation 3)

In addition, “modulation signal 2” tx2(i) with symbol number i isexpressed, for example, as follows.[4]tx2(i)=γ(i)×s1(i)+δ(i)×s2(i)  (Equation 4)

Note that in Equations 3 and 4, α(i) is defined by a complex number and,thus, may be a real number. β(i) is defined by a complex number and,thus, may be a real number. γ(i) is defined by a complex number and,thus, may be a real number. δ(i) is defined by a complex number and,thus, may be a real number. In addition, α(i) does not have to be afunction of symbol number i, and may be a fixed value, for example. β(i)does not have to be a function of symbol number i, and may be a fixedvalue, for example. γ(i) does not have to be a function of symbol numberi, and may be a fixed value, for example. δ(i) does not have to be afunction of symbol number i, and may be a fixed value, for example.

The “symbol group of modulation signal 1” including a “signal of a datatransmission region of modulation signal 1” composed of data symbols istransmitted from the base station of FIG. 1 or 3 . Further, the “symbolgroup of modulation signal 2” including a “signal of the datatransmission region of modulation signal 2” composed of data symbols istransmitted from the base station of FIG. 1 or 3 .

Note that, signal processing such as phase change and/or Cyclic DelayDiversity (CDD) may be performed on “modulation signal 1” and/or“modulation signal 2.” However, the method for signal processing is notlimited to this.

FIG. 14 illustrates an example of the frame configuration in which thehorizontal axis represents time.

The #1 symbol group (1401-1) of modulation signal 1 in FIG. 14 is asymbol group of transmission beam 1202-1 for transmitting data ofmodulation signal 1 in FIG. 12 .

The #2 symbol group (1401-2) of modulation signal 1 in FIG. 14 is asymbol group of transmission beam 1202-2 for transmitting data ofmodulation signal 1 in FIG. 12 .

The #3 symbol group (1401-3) of modulation signal 1 in FIG. 14 is asymbol group of transmission beam 1202-3 for transmitting data ofmodulation signal 1 in FIG. 12 .

The #1 symbol group (1402-1) of modulation signal 2 in FIG. 14 is asymbol group of transmission beam 1203-1 for transmitting the data ofmodulation signal 2 in FIG. 12 .

The #2 symbol group (1402-2) of modulation signal 2 in FIG. 14 is asymbol group of transmission beam 1203-2 for transmitting the data ofmodulation signal 2 in FIG. 12 .

The #3 symbol group (1402-3) of modulation signal 2 in FIG. 14 is asymbol group of transmission beam 1203-3 for transmitting the data ofmodulation signal 2 in FIG. 12 .

The #1 symbol group (1401-1) of modulation signal 1, #2 symbol group(1401-2) of modulation signal 1, #3 symbol group (1401-3) of modulationsignal 1, #1 symbol group (1402-1) of modulation signal 2, #2 symbolgroup (1402-2) of modulation signal 2, and #3 symbol group (1402-3) ofmodulation signal 2 exist, for example, in time section 1.

As described above, #1 symbol group (1401-1) of modulation signal 1 and#1 symbol group (1402-1) of modulation signal 2 are transmitted usingthe same frequency (the same frequency band). The #2 symbol group(1401-2) of modulation signal 1 and #2 symbol group (1402-2) ofmodulation signal 2 are transmitted using the same frequency (the samefrequency band). The #3 symbol group (1401-3) of modulation signal 1 and#3 symbol group (1402-3) of modulation signal 2 are transmitted usingthe same frequency (the same frequency band).

For example, in accordance with the procedure of FIG. 13 , “signals A ofthe data transmission region of modulation signal 1” and “signals A ofthe data transmission region of modulation signal 2” are generated fromthe information. Then, “signals A-1 of the data transmission region ofmodulation signal 1” composed of signals equivalent to thoseconstituting “signals A of the data transmission region of modulationsignal 1” are prepared. The “signals A-2 of the data transmission regionof modulation signal 1” composed of signals equivalent to thoseconstituting “signals A of the data transmission region of modulationsignal 1” are prepared. The “signals A-3 of the data transmission regionof modulation signal 1” composed of signals equivalent to thoseconstituting “signals A of the data transmission region of modulationsignal 1” are prepared.

That is, the signals constituting “signal group A-1 of the datatransmission region of modulation signal 1,” the signals constituting“signals A-2 of the data transmission region of modulation signal 1” andthe signals constituting the “signals A-3 of the data transmissionregion of modulation signal 1” are the same.

In this case, #1 symbol group (1401-1) of modulation signal 1 of FIG. 14includes “signals A-1 of the data transmission region of modulationsignal 1.” The #2 symbol group (1401-2) of modulation signal 1 of FIG.14 includes “signals A-2 of the data transmission region of modulationsignal 1.” The #3 symbol group (1401-3) of modulation signal 1 of FIG.14 includes “signals A-3 of the data transmission region of modulationsignal 1.” In other words, #1 symbol group (1401-1) of modulation signal1, #2 symbol group (1401-2) of modulation signal 1, and #3 symbol group(1401-3) of modulation signal 1 include equivalent signals.

Further, “signals A-1 of the data transmission region of modulationsignal 2” composed of signals equivalent to those constituting “signalsA of the data transmission region of modulation signal 2” are prepared.The “signals A-2 of the data transmission region of modulation signal 2”composed of signals equivalent to those constituting “signals A of thedata transmission region of modulation signal 2” are prepared. The“signals A-3 of the data transmission region of modulation signal 2”composed of signals equivalent to those constituting “signals A of thedata transmission region of modulation signal 2” are prepared.

That is, the signals constituting “signals A-1 of the data transmissionregion of modulation signal 2,” the signals constituting “signals A-2 ofthe data transmission region of modulation signal 2,” and the signalsconstituting the “signals A-3 of the data transmission region ofmodulation signal 2” are the same.

In this case, #1 symbol group (1402-1) of modulation signal 2 in FIG. 14includes “signals A-1 of the data transmission region of modulationsignal 2.” The #2 symbol group (1402-2) of stream 2 in FIG. 14 includes“signals A-2 in the data transmission region of modulation signal 2.”The #3 symbol group (1402-3) of modulation signals 2 of FIG. 14 includes“signals A-3 of the data transmission region of modulation signal 2.” Inother words, #1 symbol group (1402-1) of modulation signal 2, #2 symbolgroup (1402-2) of modulation signal 2, and #3 symbol group (1402-3) ofmodulation signal 2 include equivalent signals.

FIG. 15 illustrates an example of the frame configuration of “symbolgroup #Y of modulation signal X” (X=1 or 2; Y=1, 2, or 3) described inFIG. 14 . In FIG. 15 , the horizontal axis represents the timedirection, and control information symbol 1501 and modulation signaltransmission region 1502 for data transmission are arranged in the timeaxis direction. In this case, modulation signal transmission region 1502for data transmission is a symbol for transmitting “signals A of thedata transmission region of modulation signal 1” or “signals A of thedata transmission region of modulation signal 2” described withreference to FIG. 14 .

Note that, a multi-carrier system such as an Orthogonal FrequencyDivision Multiplexing (OFDM) scheme may be used for the frameconfiguration of FIG. 15 , and in this case, symbols may be present inthe frequency-axis direction. In addition, each of the symbols mayinclude a reference symbol for a reception apparatus to perform time andfrequency synchronization, a reference symbol for the receptionapparatus to detect a signal, a reference symbol for the receptionapparatus to perform channel estimation, and/or the like. The frameconfiguration is not limited to that illustrated in FIG. 15 , andcontrol information symbol 1501 and modulation signal transmissionregion 1502 for data transmission may also be arranged in any manner.The reference symbol may also be referred to as a preamble or a pilotsymbol.

Next, the configuration of control information symbol 1501 will bedescribed.

FIG. 16 illustrates an example of a configuration of a symbol to betransmitted as the control information symbol in FIG. 15 . In FIG. 16 ,the horizontal axis represents time. In FIG. 16 , the terminal receives“training symbol 1601 for a terminal to perform reception directivitycontrol” to determine a signal processing method for receptiondirectivity control performed at “signal processor 405,” “antennas 401-1to 401-N,” and/or “multipliers 603-1 to 603-L and processor 605.”

The terminal receives “symbol 1602 for indicating the number oftransmission modulation signals used when multicast is being performed,”so as to be able to know the number of modulation signals to beobtained.

The terminal receives “symbol 1603 for indicating which modulationsignal transmission region for modulation-signal data transmission themodulation signal transmission region for modulation-signal datatransmission is,” so as to be able to know which one of the modulationsignals being transmitted by the base station has been successfullyreceived.

An example of the above will be described.

The case where the base station transmits transmission beams of“modulation signals” as illustrated in FIG. 12 will be considered.Further, a description will be given of specific information of thecontrol information symbol in #1 symbol group 1401-1 of modulationsignal 1 in FIG. 14 .

Since the base station transmits “modulation signal 1” and “modulationsignal 2” in the case of FIG. 12 , the information of “symbol 1602 forindicating the number of transmission modulation signals used whenmulticast is being performed” is “2.”

Since #1 symbol group 1401-1 of modulation signal 1 in FIG. 14 sends thesignal of the data transmission region of modulation signal 1, theinformation of “symbol 1603 for indicating which modulation signaltransmission region for modulation-signal data transmission themodulation signal transmission region for modulation-signal datatransmission is” is “modulation signal 1.”

For example, a description will be given of the case where the terminalreceives #1 symbol group 1401-1 of modulation signal 1 in FIG. 14 . Atthis time, the terminal recognizes, from “symbol 1602 for indicating thenumber of transmission modulation signals used when multicast is beingperformed,” that the information “the number of transmission modulationsignals is 2” has been obtained, and, from “symbol 1603 for indicatingwhich modulation signal transmission region for modulation-signal datatransmission the modulation signal transmission region formodulation-signal data transmission is,” that the information“modulation signal 1” has been obtained.

Then, since the terminal recognizes that “the number of transmissionmodulation signals is 2” and the obtained modulation signal is“modulation signal 1,” the terminal recognizes that “modulation signal2” is to be obtained. Thus, the terminal can begin operation ofsearching for “modulation signal 2.” For example, the terminal searchesfor the transmission beam of any of “#1 symbol group 1402-1 ofmodulation signal 2,” “#2 symbol group 1402-2 of modulation signal 2,”and “#3 symbol group 1402-3 of modulation signal 2 in FIG. 14 .

Then, the terminal obtains the transmission beam of any of “#1 symbolgroup 1402-1 of modulation signal 2,” “#2 symbol group 1402-2 ofmodulation signal 2,” and “#3 symbol group 1402-3 of modulation signal2,” to obtain both of “modulation signal 1” and “modulation signal 2.”Thus, the terminal is capable of obtaining the data symbols of stream 1and the data symbols of stream 2 with high quality.

As an effect of the present embodiment, the control information symbolconfigured as described above allows the terminal to accurately obtaindata symbols.

As described above, in the multicast data transmission and the broadcastdata transmission, the base station transmits data symbols using aplurality of transmission beams, and the terminal selectively receives ahigh-quality beam out of a plurality of transmission beams. Thetransmission directivity control and the reception directivity controlare performed on the modulation signal transmitted by the base station,so that, as an effect of the present embodiment, it is possible to widenan area where high data reception quality is achieved.

Note that, although the terminal performs the reception directivitycontrol in the above description, the aforementioned effects can beobtained even when the terminal does not perform the receptiondirectivity control.

Note also that each of the terminals obtains both of the modulationsignal of stream 1 and the modulation signal of stream 2 in FIG. 7 , butthe embodiment is not necessarily limited thereto. For example, theremay be a terminal which intends to obtain the modulation signal ofstream 1, a terminal which intends to obtain the modulation signal ofstream 2, a terminal which intends to obtain both of the modulationsignal of stream 1 and the modulation signal of stream 2. That is, themodulation signal that the terminal intends to obtain may be differentin the embodiment.

Embodiment 2

Embodiment 1 has been described in relation to a method in which thebase station transmits data symbols using a plurality of transmissionbeams in multicast data transmission and broadcast data transmission.The present embodiment as a variation of Embodiment 1 will be describedin relation to a case where the base station performs multicast datatransmission, broadcast data transmission, and unicast datatransmission.

FIG. 17 illustrates an example of a communication state between a basestation (or access point or the like) and terminals. Components in FIG.17 that operate in the same manner as those in FIG. 7 are provided withthe same reference numerals, and the descriptions of those componentsare omitted below.

Base station 700 includes multiple antennas and transmits a plurality oftransmission signals from transmission antenna 701. Base station 700 isconfigured, for example, as illustrated in FIG. 1 or 3 and performs, atsignal processor 102 (and/or at weighting combiner 301), precoding(weighted combination) to perform transmission beamforming (directivitycontrol) when transmitting a transmission signal.

Transmission beams 702-1, 702-2, 702-3, 703-1, 703-2, and 703-3 are asdescribed with reference to FIG. 7 and, therefore, the descriptionsthereof are omitted.

Terminals 704-1, 704-2, 704-3, 704-4, and 704-5 and receptiondirectivities 705-1, 705-2, 705-3, 705-4, 705-5, 706-1, 706-2, 706-3,706-4, and 706-5 are as described with reference to FIG. 7 and,therefore, the descriptions thereof are omitted.

In FIG. 17 , the base station performs multicast as described in FIG. 7, and further, base station 700 and the terminal (e.g., 1702) performunicast communication.

In addition to multicast transmission beams 702-1, 702-2, 702-3, 703-1,703-2, and 703-3, base station 700 generates unicast transmission beam1701 and transmits specific data to terminal 1702 in FIG. 17 . Notethat, FIG. 17 illustrates an example where base station 700 transmitsone transmission beam 1701 to terminal 1702. However, the number oftransmission beams is not limited to one. Base station 700 may transmita plurality of transmission beams (or may transmit a plurality ofmodulation signals) to terminal 1702.

Terminal 1702 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and the processor 605” to form reception directivity 1703.Terminal 1702 can thus receive and demodulate transmission beam 1701.

In order to generate transmission beams including transmission beam1701, the base station performs precoding (weighted combination) atsignal processor 102 (and/or weighting combiner 301) configured, forexample, as illustrated in FIG. 1 or 3 .

When terminal 1702 transmits a modulation signal to base station 700,terminal 1702 performs precoding (or weighted combination) and transmitstransmission beam 1703. Base station 700 performs reception directivitycontrol to form reception directivity 1701. Base station 700 can thusreceive and demodulate transmission beam 1703.

Base station 700 transmits transmission beam 702-1 for transmitting thedata of stream 1 and transmission beam 703-1 for transmitting the dataof stream 2 using the same frequency (the same frequency band) and thesame time. Base station 700 transmits transmission beam 702-2 fortransmitting the data of stream 1 and transmission beam 703-2 fortransmitting the data of stream 2 using the same frequency (the samefrequency band) and the same time. Base station 700 transmitstransmission beam 702-3 for transmitting the data of stream 1 andtransmission beam 703-3 for transmitting the data of stream 2 using thesame frequency (the same frequency band) and the same time.

Note that, transmission beams 702-1, 702-2, and 702-3 for transmittingthe data of stream 1 may be beams of the same frequency (the samefrequency band), or may be beams of frequencies different from oneanother (frequency bands different from one another). Transmission beams703-1, 703-2, and 703-3 for transmitting the data of stream 2 may bebeams of the same frequency (the same frequency band), or may be beamsof frequencies different from one another (frequency bands differentfrom one another).

Transmission beam 1701 for unicast may be a beam of the same frequency(same frequency band) as transmission beams 702-1, 702-2, 702-3, 703-1,703-2, and 703-3, or a beam of a frequency (frequency band) differentfrom the frequency of transmission beams 702-1, 702-2, 702-3, 703-1,703-2, and 703-3.

Note that, although the description of FIG. 17 has been given in whichone terminal performs unicast communication, a plurality of terminalsmay perform unicast communication with the base station.

The operation of setter 158 in the configuration of the base stationillustrated in FIG. 1 or 3 will be described.

Configuration signal 160 is input to setter 158. Configuration signal160 includes information indicating “whether to perform multicasttransmission and/or to perform unicast transmission.” When the basestation performs transmission as illustrated in FIG. 17 , configurationsignal 160 provides input of the information “both multicasttransmission and unicast transmission are to be performed” into setter158.

Configuration signal 160 includes information indicating “the number oftransmission streams for multicasting.” When the base station performstransmission as illustrated in FIG. 17 , configuration signal 160provides input of the information “the number of transmission streams is2” into setter 158.

Configuration signal 160 may include information indicating “how manytransmission beams are used to transmit each stream.” When the basestation performs transmission as illustrated in FIG. 17 , configurationsignal 160 provides input of the information “the number of transmissionbeams for transmitting stream 1 is 3 and the number of transmissionbeams for transmitting stream 2 is 3” into setter 158.

The base station of FIG. 1 or 3 may transmit a control informationsymbol including information indicating whether data symbols are“multicast transmission and/or unicast transmission,” informationindicating “the number of transmission streams for multicasting,” and/orinformation indicating “how many transmission beams are used to transmiteach stream,” and the like. It is thus possible for the terminal toperform suitable reception.

The base station may transmit, to the terminal with which the basestation performs the unicast communication, a training controlinformation symbol for the base station to perform the directivitycontrol and/or a training control information symbol for the terminal toperform the directivity control.

FIG. 18 illustrates an example of a communication state between a basestation (or access point or the like) and terminals. Components in FIG.18 that operate in the same manner as those in FIG. 7 or 12 are providedwith the same reference numerals, and the descriptions of thosecomponents are omitted below.

Base station 700 includes multiple antennas and transmits a plurality oftransmission signals from transmission antenna 701. Base station 700 isconfigured, for example, as illustrated in FIG. 1 or 3 and performs, atsignal processor 102 (and/or at weighting combiner 301), precoding(weighted combination) to perform transmission beamforming (directivitycontrol) when transmitting a transmission signal.

Transmission beams 1202-1, 1202-2, 1202-3, 1203-1, 1203-2, and 1203-3are as described with reference to FIG. 12 and, therefore, thedescriptions thereof are omitted.

Terminals 704-1, 704-2, 704-3, 704-4, and 704-5 and receptiondirectivities 705-1, 705-2, 705-3, 705-4, 705-5, 706-1, 706-2, 706-3,706-4, and 706-5 are as described with reference to FIG. 12 and,therefore, the descriptions thereof are omitted.

In FIG. 18 , the base station performs multicast as described in FIG. 12, and further, base station 700 and the terminal (e.g., 1702) performunicast communication.

In addition to multicast transmission beams 1202-1, 1202-2, 1202-3,1203-1, 1203-2, and 1203-3, base station 700 generates unicasttransmission beams 1701 and transmits specific data to terminal 1702 inFIG. 18 . Note that, FIG. 18 illustrates an example where base station700 transmits one transmission beam 1701 to terminal 1702. However, thenumber of transmission beams is not limited to one. Base station 700 maytransmit a plurality of transmission beams (or may transmit a pluralityof modulation signals) to terminal 1702.

Terminal 1702 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and the processor 605” to form reception directivity 1703.Terminal 1702 can thus receive and demodulate transmission beam 1701.

In order to generate transmission beams including transmission beam1701, the base station performs precoding (weighted combination) atsignal processor 102 (and/or weighting combiner 301) configured, forexample, as illustrated in FIG. 1 or 3 .

When terminal 1702 transmits a modulation signal to base station 700,terminal 1702 performs precoding (or weighted combination) and transmitstransmission beam 1701. Base station 700 performs reception directivitycontrol to form reception directivity 1703. Base station 700 can thusreceive and demodulate transmission beam 1701.

Base station 700 transmits transmission beam 1202-1 for transmitting“modulation signal 1” and transmission beam 1203-1 for transmitting“modulation signal 2” using the same frequency (the same frequency band)and the same time. Base station 700 transmits transmission beam 1202-2for transmitting “modulation signal 1” and transmission beam 1203-2 fortransmitting “modulation signal 2” using the same frequency (the samefrequency band) and the same time. Base station 700 transmitstransmission beam 1202-3 for transmitting “modulation signal 1” andtransmission beam 1203-3 for transmitting “modulation signal 2” usingthe same frequency (the same frequency band) and the same time.

Note that, transmission beams 1202-1, 1202-2, and 1202-3 fortransmitting “modulation signal 1” may be beams of the same frequency(the same frequency band) or may be beams of frequencies (frequencybands) different from one another. Transmission beams 1203-1, 1203-2,and 1203-3 for transmitting “modulation signal 2” may be beams of thesame frequency (the same frequency band) or may be beams of frequencies(frequency bands) different from one another.

Unicast transmission beam 1701 may be a beam of the same frequency (samefrequency band) as transmission beams 1202-1, 1202-2, 1202-3, 1203-1,1203-2, and 1203-3, or a beam of a frequency (frequency band) differentfrom the frequency of transmission beams 1202-1, 1202-2, 1202-3, 1203-1,1203-2, and 1203-3.

Note that, although the description of FIG. 18 has been given in whichone terminal performs unicast communication, a plurality of terminalsmay perform unicast communication with the base station.

The operation of setter 158 of the base station illustrated in FIG. 1 or3 for the above case will be described.

Configuration signal 160 is input to setter 158. Configuration signal160 includes information indicating “whether to perform multicasttransmission and/or to perform unicast transmission.” When the basestation performs transmission as illustrated in FIG. 18 , configurationsignal 160 provides input of the information “both multicasttransmission and unicast transmission are to be performed” into setter158.

Configuration signal 160 includes information indicating “the number oftransmission streams for multicasting.” When the base station performstransmission as illustrated in FIG. 18 , configuration signal 160provides input of the information “the number of transmission streams is2” into setter 158.

Configuration signal 160 may include information indicating “how manytransmission beams are used to transmit each stream.” When the basestation performs transmission as illustrated in FIG. 18 , configurationsignal 160 provides input of the information “the number of transmissionbeams for transmitting stream 1 is 3 and the number of transmissionbeams for transmitting stream 2 is 3” into setter 158.

The base station of FIG. 1 or 3 may transmit a control informationsymbol including information indicating whether data symbols are“multicast transmission and/or unicast transmission,” informationindicating “the number of transmission streams for multicasting,” and/orinformation indicating “how many transmission beams are used to transmiteach stream,” and the like. It is thus possible for the terminal toperform suitable reception.

The base station may transmit, to the terminal with which the basestation performs the unicast communication, a training controlinformation symbol for the base station to perform the directivitycontrol and/or a training control information symbol for the terminal toperform the directivity control.

Next, as a variation of Embodiment 1, a case in which the base stationtransmits a plurality of multicast data transmissions will be described.

FIG. 19 illustrates an example of a communication state between a basestation (or access point or the like) and terminals. Components in FIG.19 that operate in the same manner as those in FIG. 7 are provided withthe same reference numerals, and the descriptions of those componentsare omitted below.

Base station 700 includes multiple antennas and transmits a plurality oftransmission signals from transmission antenna 701. Base station 700 isconfigured, for example, as illustrated in FIG. 1 or 3 and performs, atsignal processor 102 (and/or at weighting combiner 301), precoding(weighted combination) to perform transmission beamforming (directivitycontrol) when transmitting a transmission signal.

Transmission beams 702-1, 702-2, 702-3, 703-1, 703-2, and 703-3 are asdescribed with reference to FIG. 7 and, therefore, the descriptionsthereof are omitted.

Terminals 704-1, 704-2, 704-3, 704-4, and 704-5 and receptiondirectivities 705-1, 705-2, 705-3, 705-4, 705-5, 706-1, 706-2, 706-3,706-4, and 706-5 are as described with reference to FIG. 7 and,therefore, the descriptions thereof are omitted.

Base station 700 transmits transmission beams 1901-1, 1901-2, 1902-1,and 1902-2 in addition to transmission beams 702-1, 702-2, 702-3, 703-1,703-2, and 703-3.

Transmission beam 1901-1 is a transmission beam for transmitting data ofstream 3. Transmission beam 1901-2 is also a transmission beam fortransmitting the data in stream 3. Transmission beam 1902-1 is atransmission beam for transmitting data of stream 4. Transmission beam1902-2 is also a transmission beam for transmitting the data of stream4.

Terminals 704-1, 704-2, 704-3, 704-4, 704-5, 1903-1, 1903-2, and 1903-3are configured, for example, as illustrated in FIGS. 4 and 5 . Notethat, the operations of terminals 704-1, 704-2, 704-3, 704-4, and 704-5are as described with reference to FIG. 7 .

Terminal 1903-1 performs reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and processor 605” to form reception directivity 1904-1 andreception directivity 1905-1. Reception directivity 1904-1 allowsterminal 1903-1 to receive and demodulate transmission beam 1901-2 fortransmitting the data of stream 3, and reception directivity 1905-1allows terminal 1903-1 to receive and demodulate transmission beam1902-2 for transmitting the data of stream 4.

Terminal 1903-2 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and processor 605” to form reception directivity 1904-2 andreception directivity 1905-2. Reception directivity 1904-2 allowsterminal 1903-2 to receive and demodulate transmission beam 1902-1 fortransmitting the data of stream 4, and reception directivity 1905-2allows terminal 1903-2 to receive and demodulate transmission beam1901-2 for transmitting the data of stream 3.

Terminal 1903-3 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and processor 605” to form reception directivity 1904-3 andreception directivity 1905-3. Reception directivity 1904-3 allowsterminal 1903-3 to receive and demodulate transmission beam 1901-1 fortransmitting the data of stream 3, and reception directivity 1905-3allows terminal 1903-3 to receive and demodulate transmission beam1902-1 for transmitting the data of stream 4.

Terminal 1903-4 performs the reception directivity control at “signalprocessor 405,” “antennas 401-1 to 401-N,” and/or “multipliers 603-1 to603-L and processor 605” to form reception directivity 1904-4 andreception directivity 1905-4. Reception directivity 1904-4 allowsterminal 1903-4 to receive and demodulate transmission beam 703-1 fortransmitting the data of stream 2, and reception directivity 1905-4allows terminal 1903-4 to receive and demodulate transmission beam1901-1 for transmitting the data of stream 3.

In FIG. 19 , the base station transmits a plurality of streams includingmulticast data. Further, each of the streams is transmitted by aplurality of transmission beams. Each of the terminals selectivelyreceives a transmission beam of one or more streams among the pluralityof streams.

Base station 700 transmits transmission beam 702-1 for transmitting thedata of stream 1 and transmission beam 703-1 for transmitting the dataof stream 2 using the same frequency (the same frequency band) and thesame time. Base station 700 transmits transmission beam 702-2 fortransmitting the data of stream 1 and transmission beam 703-2 fortransmitting the data of stream 2 using the same frequency (the samefrequency band) and the same time. Base station 700 transmitstransmission beam 702-3 for transmitting the data of stream 1 andtransmission beam 703-3 for transmitting the data of stream 2 using thesame frequency (the same frequency band) and the same time.

Base station 700 transmits transmission beam 1901-1 for transmitting thedata of stream 3 and transmission beam 1902-1 for transmitting the dataof stream 4 using the same frequency (the same frequency band) and thesame time. Base station 700 transmits transmission beams 1901-2 fortransmitting the data of stream 3 and transmission beams 1902-2 fortransmitting the data of stream 4 using the same frequency (the samefrequency band) and the same time.

Note that, transmission beams 702-1, 702-2, and 702-3 for transmittingthe data of stream 1 may be beams of the same frequency (the samefrequency band), or may be beams of frequencies different from oneanother (frequency bands different from one another). Transmission beams703-1, 703-2, and 703-3 for transmitting the data of stream 2 may bebeams of the same frequency (the same frequency band), or may be beamsof frequencies different from one another (frequency bands differentfrom one another).

Transmission beams 1901-1 and 1901-2 for transmitting the data of stream3 may be beams of the same frequency (the same frequency band) or beamsof frequencies (frequency bands) different from each other. Transmissionbeams 1902-1 and 1902-2 for transmitting the data of stream 4 may bebeams of the same frequency (the same frequency band) or beams offrequencies (frequency bands) different from each other.

Further, the data symbols of stream 1 and the data symbols of stream 2may be generated from #1 information 101-1 in FIG. 1 , and the datasymbols of stream 3 and the data symbols of stream 4 may be generatedfrom #2 information 101-2. Alternatively, the data symbols may begenerated after error correction coding is performed on #1 information101-1 and #2 information 101-2.

Further, the data symbols of stream 1 may be generated from #1information 101-1 in FIG. 1 , the data symbols of stream 2 may begenerated from #2 information 101-2 in FIG. 1 , the data symbols ofstream 3 may be generated from #3 information 101-3 in FIG. 1 , and thedata symbols of stream 4 may be generated from #4 information 101-4 inFIG. 1 . Note that, the data symbols may be generated after errorcorrection coding is performed on #1 information 101-1, #2 information101-2, #3 information 101-3, and #4 information 101-4.

That is, the data symbols of each of the streams may be generated fromany information in FIG. 1 . Thus, as an effect of the presentembodiment, the terminal can selectively obtain a multicast stream.

The operation of setter 158 of the base station illustrated in FIG. 1 or3 for the above case will be described.

Configuration signal 160 is input to setter 158. Configuration signal160 includes information indicating “whether to perform multicasttransmission and/or to perform unicast transmission.” When the basestation performs transmission as illustrated in FIG. 19 , configurationsignal 160 provides input of the information “multicast transmission isto be performed” into setter 158.

Configuration signal 160 includes information indicating “the number oftransmission streams for multicasting.” When the base station performstransmission as illustrated in FIG. 19 , information “the number oftransmission streams is 4” is input to setter 158 by configurationsignal 160.

Configuration signal 160 may include information indicating “how manytransmission beams are used to transmit each stream.” When the basestation performs transmission as illustrated in FIG. 19 , configurationsignal 160 provides input of the information “the number of transmissionbeams for transmitting stream 1 is 3, the number of transmission beamsfor transmitting stream 2 is 3, the number of transmission beams fortransmitting stream 3 is 2, and the number of transmission beams fortransmitting stream 4 is 2” into setter 158.

The base station of FIG. 1 or 3 may transmit a control informationsymbol including information indicating whether data symbols are“multicast transmission and/or unicast transmission,” informationindicating “the number of transmission streams for multicasting,” and/orinformation indicating “how many transmission beams are used to transmiteach stream,” and the like. It is thus possible for the terminal toperform suitable reception.

Next, as a variation of Embodiment 1, a case in which the base stationtransmits a plurality of multicast data transmissions will be described.

FIG. 20 illustrates an example of a communication state between a basestation (or an access point or the like) and terminals. Components inFIG. 20 that operate in the same manner as those in FIG. 7, 12 , or 19are provided with the same reference numerals, and the descriptions ofthose components are omitted below.

Base station 700 includes multiple antennas and transmits a plurality oftransmission signals from transmission antenna 701. Base station 700 isconfigured, for example, as illustrated in FIG. 1 or 3 and performs, atsignal processor 102 (and/or at weighting combiner 301), precoding(weighted combination) to perform transmission beamforming (directivitycontrol) when transmitting a transmission signal.

Transmission beams 1202-1, 1202-2, 1202-3, 1203-1, 1203-2, and 1203-3are as described with reference to FIG. 12 and, therefore, thedescriptions thereof are omitted.

Terminals 704-1, 704-2, 704-3, 704-4, and 704-5 and receptiondirectivities 705-1, 705-2, 705-3, 705-4, 705-5, 706-1, 706-2, 706-3,706-4, and 706-5 are as described with reference to FIG. 12 and,therefore, the descriptions thereof are omitted.

Base station 700 transmits transmission beams 2001-1, 2001-2, 2002-1,and 2002-2 in addition to transmission beams 1202-1, 1202-2, 1202-3,1203-1, 1203-2, and 1203-3.

Transmission beam 2001-1 is a transmission beam for transmitting“modulation signal 3.” Transmission beam 2001-2 is also a transmissionbeam for transmitting “modulation signal 3.”

Transmission beam 2002-1 is a transmission beam for transmitting“modulation signal 4.” Transmission beam 2002-2 is also a transmissionbeam for transmitting “modulation signal 4.”

Terminals 704-1, 704-2, 704-3, 704-4, 704-5, 1903-1, 1903-2, and 1903-3have, for example, the same configurations as in FIGS. 4 and 5 . Notethat, the operations of terminals 704-1, 704-2, 704-3, 704-4, and 704-5are the same as those described with reference to FIG. 7 .

Terminal 1903-1 performs directivity control for reception by “signalprocessor 405,” “antenna 401-1 to antenna 401-N,” and/or “multiplier603-1 to multiplier 603-L, and processor 605,” to form receptiondirectivity 1904-1 and reception directivity 1905-1. Receptiondirectivity 1904-1 allows terminal 1903-1 to receive and demodulatetransmission beam 2001-2 for transmitting “modulation signal 3,” andreception directivity 1905-1 allows terminal 1903-1 to receive anddemodulate transmission beam 2002-2 for transmitting “modulation signal4.”

Terminal 1903-2 performs directivity control for reception by “signalprocessor 405,” “antenna 401-1 to antenna 401-N,” and/or “multiplier603-1 to multiplier 603-L, and processor 605,” to form receptiondirectivity 1904-2 and reception directivity 1905-2. Receptiondirectivity 1904-2 allows terminal 1903-2 to receive and demodulatetransmission beam 2002-1 for transmitting “modulation signal 4,” andreception directivity 1905-2 allows terminal 1903-2 to receive anddemodulate transmission beam 2001-2 for transmitting “modulation signal3.”

Terminal 1903-3 performs directivity control for reception by “signalprocessor 405,” “antenna 401-1 to antenna 401-N,” and/or “multiplier603-1 to multiplier 603-L, and processor 605,” to form receptiondirectivity 1904-3 and reception directivity 1905-3. Receptiondirectivity 1904-3 allows terminal 1903-3 to receive and demodulatetransmission beam 2001-1 for transmitting “modulation signal 3,” andreception directivity 1905-3 allows terminal 1903-3 to receive anddemodulate transmission beam 2002-1 for transmitting “modulation signal4.”

Terminal 1903-4 performs directivity control for reception by “signalprocessor 405,” “antenna 401-1 to antenna 401-N,” and/or “multiplier603-1 to multiplier 603-L, and processor 605,” to form receptiondirectivity 1904-4 and reception directivity 1905-4. Receptiondirectivity 1904-4 allows terminal 1903-4 to receive and demodulatetransmission beam 2001-1 for transmitting “modulation signal 3,” andreception directivity 1905-4 allows terminal 1903-4 to receive anddemodulate transmission beam 2002-1 for transmitting “modulation signal4.”

In FIG. 20 , the base station transmits a plurality of modulationsignals including multicast data. Each of the modulation signals istransmitted by a plurality of transmission beams. Each of the terminalsselectively receives a transmission beam of one or more streams amongthe plurality of modulation signals.

Base station 700 transmits transmission beam 1202-1 for transmitting“modulation signal 1” and transmission beam 1203-1 for transmitting“modulation signal 2” using the same frequency (the same frequency band)and the same time. Base station 700 transmits transmission beam 1202-2for transmitting “modulation signal 1” and transmission beam 1203-2 fortransmitting “modulation signal 2” using the same frequency (the samefrequency band) and the same time. Base station 700 transmitstransmission beam 1202-3 for transmitting “modulation signal 1” andtransmission beam 1203-3 for transmitting “modulation signal 2” usingthe same frequency (the same frequency band) and the same time.

Base station 700 transmits transmission beam 2001-1 for transmitting“modulation signal 3” and transmission beam 2002-1 for transmitting“modulation signal 4” using the same frequency (the same frequency band)and the same time. Base station 700 transmits transmission beam 2001-2for transmitting “modulation signal 3” and transmission beam 2002-2 fortransmitting “modulation signal 4” using the same frequency (the samefrequency band) and the same time.

Note that, transmission beams 702-1, 702-2, and 702-3 for transmittingthe data of stream 1 may be beams of the same frequency (the samefrequency band), or may be beams of frequencies (frequency bands)different from one another. Transmission beams 703-1, 703-2, and 703-3for transmitting the data of stream 2 may be beams of the same frequency(the same frequency band), or may be beams of frequencies (frequencybands) different from one another.

Transmission beams 2001-1 and 2001-2 for transmitting “modulation signal3” may be beams of the same frequency (the same frequency band), or maybe beams of frequencies (frequency bands) different from one another.Transmission beams 2002-1 and 2002-2 for transmitting “modulation signal4” may be beams of the same frequency (the same frequency band), or maybe beams of frequencies (frequency bands) different from one another.

The operation of setter 158 in the configuration of the base stationillustrated in FIG. 1 or 3 will be described.

Configuration signal 160 is input to setter 158. Configuration signal160 includes information indicating “whether to perform multicasttransmission and/or to perform unicast transmission.” When the basestation performs transmission as illustrated in FIG. 19 , configurationsignal 160 provides input of the information “multicast transmission isto be performed” into setter 158.

Configuration signal 160 includes information indicating “the number oftransmission modulation signals for multicasting.” When the base stationperforms the transmission illustrated in FIG. 20 , configuration signal160 provides input of the information “the number of transmissionmodulation signals is 4” into setter 158.

Configuration signal 160 may include information indicating “how manytransmission beams are used to transmit each modulation signal.” Whenthe base station performs transmission as illustrated in FIG. 20 ,configuration signal 160 provides input of the information “the numberof transmission beams for transmitting modulation signal 1 is 3, thenumber of transmission beams for transmitting modulation signal 2 is 3,the number of transmission beams for transmitting modulation signal 3 is2, and the number of transmission beams for transmitting modulationsignal 4 is 2” into setter 158.

Note that, the base station of FIG. 1 or 3 may transmit a controlinformation symbol including information indicating whether data symbolsare “multicast transmission/unicast transmission,” informationindicating “the number of transmission streams for multicasting,” and/orinformation indicating “how many transmission beams are used to transmiteach stream,” and the like. It is thus possible for the terminal toperform suitable reception.

In FIG. 20 , the terminal can obtain the data of stream 1 and the dataof stream 2 with high reception quality when receiving both thetransmission beam of “modulation signal 1” and the transmission beam of“modulation signal 2.” Similarly, the terminal can obtain the data ofstream 3 and the data of stream 4 with high reception quality whenreceiving both the transmission beam of “modulation signal 3” and thetransmission beam of “modulation signal 4.”

FIG. 20 illustrates an example in which the base station transmits“modulation signal 1,” “modulation signal 2,” “modulation signal 3,” and“modulation signal 4,” but this is an example. The base station mayfurther transmit “modulation signal 5” and “modulation signal 6” fortransmitting the data of stream 5 and the data of stream 6,respectively, or may also transmit more modulation signals fortransmitting more streams than mentioned above. Note that, each of themodulation signals is transmitted using one or more transmission beams.

Note also that, as described with reference to FIGS. 17 and 18 , theremay be one or more unicast transmission beams (or one or more unicastreception directivity controls) in FIG. 20 .

The relationship between “modulation signal 1” and “modulation signal 2”is as described with reference to FIG. 13 and, therefore, thedescription thereof is omitted. Here, the relationship between“modulation signal 3” and “modulation signal 4” will be described withreference to FIG. 21 .

For example, processing such as error correction coding is performed on#2 information 101-2 to obtain data after the error correction coding.This data after the error correction coding is called “#2 transmissiondata.” Then, mapping is performed on the #2 transmission data to obtaindata symbols. Then, the data symbols are distributed to stream 3 andstream 4 to obtain data symbols (data symbol group) of stream 3 and datasymbols (data symbol group) of stream 4. One of the data symbols ofstream 3 with symbol number i is expressed as s3(i), and one of the datasymbols of stream 4 with symbol number i is expressed as s4(i). In thiscase, “modulation signal 3” tx3(i) with symbol number i is expressed,for example, as follows.[5]tx3(i)=e(i)×s3(i)+f(i)×s4(i)  (Equation 5)

The “modulation signal 4” tx4(i) with symbol number i is expressed, forexample, as follows.[6]tx4(i)=g(i)×s3(i)+h(i)×s4(i)  (Equation 6)

In Equations 5 and 6, e(i), f(i), g(i), and h(i) are defined by complexnumbers and may be real numbers, respectively. In addition, each ofe(i), f(i), g(i), and h(i) does not have to be a function of symbolnumber i, and may be a fixed value.

The “symbol group of modulation signal 3” including a “signal of a datatransmission region of modulation signal 3” composed of data symbols istransmitted from the base station of FIG. 1 or 3 . Further, the “symbolgroup of modulation signal 4” including a “signal of a data transmissionregion of modulation signal 4” composed of data symbols is transmittedfrom the base station of FIG. 1 or 3 .

(Supplement)

It is needless to say that the embodiments described in the presentspecification may be implemented by combining a plurality ofmiscellaneous contents.

The embodiments and the miscellaneous contents are merely examples. Forexample, the present disclosure can be implemented with the sameconfiguration as described above even when a different “modulationscheme, error correction coding scheme (error correction code, codelength, coding rate, and the like for use), control information, and thelike” are applied instead of the illustrations of “modulation scheme,error correction coding scheme (used error correction code, code length,coding rate, and the like for use), control information, and the like.”

The embodiments and miscellaneous contents described in the presentspecification can also be implemented using a modulation scheme otherthan the modulation scheme described in the present specification. Forexample, Amplitude Phase Shift Keying (APSK), Pulse Amplitude Modulation(PAM), Phase Shift Keying (PSK), and/or Quadrature Amplitude Modulation(QAM) may be applied, and uniform mapping and non-uniform mapping may beused in each of the modulation schemes. APSK includes 16APSK, 64APSK,128APSK, 256APSK, 1024APSK, and 4096APSK, for example. PAM includes4PAM, 8PAM, 16PAM, 64PAM, 128PAM, 256PAM, 1024PAM, and 4096PAM, forexample. PSK includes BPSK, QPSK, 8PSK, 16PSK, 64PSK, 128PSK, 256PSK,1024PSK, and 4096PSK, for example. QAM includes 4QAM, 8QAM, 16QAM,64QAM, 128QAM, 256QAM, 1024QAM, and 4096QAM, for example.

The method of arranging signal points (e.g., 2, 4, 8, 16, 64, 128, 256,or 1024 signal points) on the I-Q plane (modulation scheme with 2, 4, 8,16, 64, 128, 256, or 1024 signal points or other number of signalpoints) is not limited to the signal-point arrangement method of themodulation scheme indicated in the present specification.

The “base station” described in the present specification may be, forexample, a broadcasting station, a base station, an access point, aterminal, a mobile phone, or the like. The “terminal” described in thepresent specification may be a television, a radio, a terminal, apersonal computer, a mobile phone, an access point, a base station, orthe like. The “base station” and the “terminal” in the presentdisclosure may be devices having a communication function, and thedevices may be configured to be capable of being connected via someinterface to an apparatus for executing an application of a television,a radio, a personal computer, a mobile phone, or the like. In addition,symbols other than data symbols (e.g., a pilot symbol, a controlinformation symbol, and the like) may be arranged in any manner in aframe in the present embodiment.

The pilot symbol and/or the control information symbol may be called byany name. The pilot symbol may be a known symbol modulated using PSKmodulation in a transceiver, for example. Alternatively, in thetransceiver, a receiver may synchronize with a transmitter to be able toknow a symbol transmitted by the transceiver. The receiver performsfrequency synchronization, time synchronization, channel estimation ofeach modulation signal (estimation of Channel State Information (CSI)),signal detection, and the like using this symbol. Note that, the pilotsymbol may be referred to as a preamble, a unique word, a postamble, areference symbol, or the like.

The control information symbol is a symbol for transmitting informationother than data (data of an application or the like) that is to betransmitted to a communication partner (for example, a modulationscheme, an error correction coding scheme, a coding rate of the errorcorrection coding scheme, configuration information of a higher layer,and/or the like used for communication) for realizing communication.

Note that the present disclosure is not limited to each of theembodiments, and can be implemented with various modifications. Forexample, each of the embodiments has been described in relation to acase where a communication apparatus performs the communication method,but the present invention is not limited to this, and the communicationmethod can be performed as software processing.

For example, a program for executing the above-described communicationmethod may be stored in a Read Only Memory (ROM) in advance, and theprogram may be operated by a Central Processor Unit CPU).

Alternatively, a computer may be operated in accordance with the programfor executing the above-described communication method, which is storedin a computer-readable storage medium and recorded in a Random AccessMemory (RAM) of the computer.

The configurations of each of the above-described embodiments maytypically be implemented as a Large Scale Integration (LSI) that is anintegrated circuit having an input terminal and an output terminal.These configurations may be individually formed into single chips, ormay be formed into one chip to include all or some of the configurationsof each of the embodiments. The LSI may be referred to as an IntegratedCircuit (IC), a system LSI, a super LSI, or an ultra LSI depending on adifference in the degree of integration. In addition, the technique ofcircuit integration is not limited to the LSI, and it may be realized bya dedicated circuit or a general-purpose processor. A Field ProgrammableGate Array (FPGA) that can be programmed after LSI fabrication or areconfigurable processor that can reconfigure connections and settingsof circuit cells inside the LSI may be used. If future integratedcircuit technology replaces LSIs as a result of the advancement ofsemiconductor technology or other derivative technology, the functionalblocks could be integrated using the future integrated circuittechnology. Biotechnology can also be applied.

Embodiment 3

The present embodiment will be described in relation to a multicastcommunication method in which beamforming different from that inEmbodiment 1 and/or Embodiment 2 is applied.

The configuration of the base station is the same as that of Embodiment1 described with reference to FIGS. 1 to 3 and, therefore, thedescription of a portion of the operation of the base station the sameas in Embodiment 1 is omitted. In addition, the configuration of theterminal that communicates with the base station is the same as thatdescribed with reference to FIGS. 4 to 6 of Embodiment 1 and, therefore,the description of a portion of the operation of the terminal the sameas in Embodiment 1 is omitted.

Hereinafter, an example of the operation of a base station and aterminal in the present embodiment will be described.

FIG. 22 illustrates a case where the base station transmits a multicasttransmission stream to one terminal.

In FIG. 22 , base station 700 transmits transmission beam 2201-1 of“(multicast) stream 1-1 (first beam of stream 1)” from a transmissionantenna to terminal 2202-1. Terminal 2202-1 performs directivity controlto generate reception directivity 2203-1, and receives transmission beam2201-1 of “stream 1-1.”

FIG. 23 explains a “procedure for performing communication between thebase station and the terminal” which is to be performed for thecommunication state between the base station and the terminal asillustrated in FIG. 22 .

[23-1] To begin with, the terminal makes a “request for multicasttransmission of stream 1” to the base station.

[23-2] On the occasion of [23-1], the base station recognizes that“multicast transmission of stream 1 is not being performed.”Accordingly, the base station transmits to the terminal a trainingsymbol for transmission directivity control and a training symbol forreception directivity control in order to perform multicast transmissionof stream 1.

[23-3] The terminal receives the training symbol for transmissiondirectivity control and the training symbol for reception directivitycontrol transmitted by the base station. Then, the terminal transmitsfeedback information to the base station in order for the base stationto perform transmission directivity control and for the terminal toperform reception directivity control.

[23-4] The base station determines a transmission directivity controlmethod (for example, determines a weighting factor used for performingdirectivity control) based on the feedback information transmitted bythe terminal. The base station then performs transmission directivitycontrol and transmits data symbols of stream 1.

[23-5] The terminal determines a reception directivity control method(for example, determines a weighting factor used for performingdirectivity control). The terminal then starts receiving the datasymbols of stream 1 transmitted by the base station.

Note that the “procedure for performing communication between the basestation and the terminal” in FIG. 23 is an example, and the order oftransmissions of information is not limited to that of FIG. 23 . Forexample, it is possible to perform the same operation even when theorder of transmissions of information is changed.

In addition, although the example in which the terminal performs thereception directivity control has been described with reference to FIG.23 , the terminal does not have to perform the reception directivitycontrol. In this case, the base station does not have to transmit thetraining symbol for reception directivity control, and the terminal doesnot have to determine the reception directivity control method in FIG.23 .

In the case where the base station performs transmission directivitycontrol and the base station has the configuration of FIG. 1 ,multiplication factors of multipliers 204-1, 204-2, 204-3, and 204-4 inFIG. 2 may be set, for example. In the case where the base station hasthe configuration of FIG. 3 , weighting factors for weighting-combiner301 may be set, for example. Note that, the number of streams to betransmitted is “1” in the case of FIG. 22 , but is not limited thereto.

In the case where the terminal performs reception directivity controland the terminal has the configuration of FIG. 4 , multiplicationfactors of multipliers 503-1, 503-2, 503-3, and 503-4 in FIG. 5 may beset, for example. In the case where the terminal has the configurationof FIG. 6 , multiplication factors of multipliers 603-1, 603-2, . . . ,and 603-L may be set, for example.

FIG. 24 illustrates an example in which symbols transmitted by the basestation and symbols transmitted by the terminal are arranged in the timedirection in a case where the base station in FIG. 23 transmits thetransmission directivity control symbol, the reception directivitycontrol symbol, and the data symbols. FIG. 24 illustrates, at (a), anexample in which the symbols transmitted by the base station arearranged in the time direction. FIG. 24 illustrates, at (b), an examplein which the symbols transmitted by the terminal are arranged in thetime direction. At (a) and (b) in FIG. 24 , the horizontal axisrepresents the time direction.

When communication is performed between the base station and theterminal as illustrated in FIG. 23 , the base station first transmits“base-station transmission-directivity-control training symbol” 2401 asillustrated in FIG. 24 . For example, base-stationtransmission-directivity-control training symbol 2401 is composed of acontrol information symbol and a known PSK symbol.

Then, the terminal receives “base-stationtransmission-directivity-control training symbol” 2401 transmitted bythe base station, and transmits, for example, information on an antennaused by the base station for transmission and information on themultiplication factor (or the weighting factor) used in directivitycontrol as feedback information symbol 2402.

The base station receives “feedback information symbol” 2402 transmittedby the terminal, and determines an antenna to be used for transmissionfrom feedback information symbol 2402. The base station also determinesa factor to be used for transmission directivity control from feedbackinformation symbol 2402. Then, the base station transmits “terminalreception-directivity-control training symbol” 2403. For example,“terminal reception-directivity-control training symbol” 2403 iscomposed of a control information symbol and a known PSK symbol.

The terminal receives “terminal reception-directivity-control trainingsymbol” 2403 transmitted by the base station, and determines, forexample, an antenna used by the terminal for reception and amultiplication factor used by the terminal for reception directivitycontrol. The terminal transmits feedback information symbol 2404 toindicate completion of preparation for receiving data symbols.

The base station receives “feedback information symbol” 2404 transmittedby the terminal, and outputs data symbols 2405 based on feedbackinformation symbol 2404.

Note that the communication between the base station and the terminalillustrated in FIG. 24 is an example. For example, the order oftransmissions of the symbols or the order of transmissions of the basestation and transmissions of the terminal is not limited to the example.Each of “base-station transmission-directivity-control training symbol”2401, “feedback information symbol” 2402, “terminalreception-directivity-control training symbol” 2403, “feedbackinformation symbol” 2404, and “data symbols” 2405 may include: apreamble, a reference symbol, and a pilot symbol for signal detection,time synchronization, frequency synchronization, frequency offsetestimation, and channel estimation; a symbol for transmitting controlinformation; and/or the like.

FIG. 25 is an example of symbols transmitted by the base station whenthe base station transmits the data symbols of stream 1 after thecommunication between the base station and the terminal in FIG. 23 iscompleted. In FIG. 25 , the horizontal axis represents the timedirection.

In FIG. 25 , the base station transmits the first data symbol oftransmission beam 1 of stream 1 as “(multicast) stream 1-1 data symbol(1)” 2501-1-1. A section in which data symbols are transmittable(hereinafter, referred to as “data-symbol-transmittable section”) 2502-1is arranged behind the first data symbol.

Thereafter, the base station transmits the second data symbol oftransmission beam 1 of (multicast) stream 1 as “(multicast) stream 1-1data symbol (2)” 2501-1-2. Data-symbol-transmittable section 2502-2 isarranged behind the second data symbol.

Thereafter, the base station transmits the third data symbol oftransmission beam 1 of (multicast) stream 1 as “(multicast) stream 1-1data symbol (3)” 2501-1-3.

In this manner, the base station transmits the data symbols of“(multicast) stream 1-1” 2201-1 illustrated in FIG. 22 . Note that, inFIG. 25 , “(multicast) stream 1-1 data symbol (1)” 2501-1-1,“(multicast) stream 1-1 data symbol (2)” 2501-1-2, “(multicast) stream1-1 data symbol (3)” 2501-1-3, and the like may include, in addition tothe data symbols, a preamble, a reference symbol, a pilot symbol forsignal detection, time synchronization, frequency synchronization,frequency offset estimation, and channel estimation, a symbol fortransmitting control information, and/or the like.

In FIG. 25 , data-symbol-transmittable section 2502-1 includes unicasttransmission section 2503-1. In addition, data-symbol-transmittablesection 2502-2 includes unicast transmission section 2503-2.

In FIG. 25 , the frame includes unicast transmission sections 2503-1 and2503-2. For example, in FIG. 25 , the base station may transmitmulticast symbols in a section of data-symbol-transmittable section2502-1 other than unicast transmission section 2503-1 and a section ofdata-symbol-transmittable section 2502-2 other than unicast transmissionsection 2503-2. Note that, a description in this respect will be givenbelow using an example.

Providing a frame with unicast transmission sections as described aboveis a useful configuration requirement for stably operating a radiocommunication system. Note that, a description in this respect will begiven below using an example. Note also that, the unicast transmissionsections do not have to be in the temporal positions as illustrated inFIG. 25 , and may be arranged in any temporal position. In the unicasttransmission sections, the base station may transmit a symbol or theterminal may transmit a symbol.

In addition, the base station may be able to directly set a unicasttransmission section. Alternatively, the base station may set a maximumtransmit data rate for transmitting multicast symbols.

For example, when the transmission rate for data transmittable by thebase station is 2 Gbps (bps: bits per second) and the maximumtransmission rate for data that the base station can allocate fortransmission of multicast symbols is 1.5 Gbps, a unicast transmissionsection equivalent to 500 Mbps can be set.

In this manner, the base station may be configured to indirectly set theunicast transmission section. Note that, another specific example willbe described below.

Note that, correspondingly to the state of FIG. 22 , FIG. 25 illustratesthe frame configuration in which “(multicast) stream 1-1 data symbol(1)” 2501-1-1, “(multicast) stream 1-1 data symbol (2)” 2501-1-2, and“(multicast) stream 1-1 data symbol (3)” 2501-1-3 are present, but thepresent disclosure is not limited thereto. For example, there may bedata symbols of a multicast stream other than stream 1 (stream 1-1),data symbols of stream 1-2 that is the second transmission beam ofstream 1, and/or data symbols of stream 1-3 that is the thirdtransmission beam of stream 1. A description will be given below in thisrespect.

FIG. 26 illustrates the state in which the base station illustrated inFIG. 22 is transmitting a multicast transmission stream to one terminaland to which one new terminal is added. Note that, components in FIG. 26that operate in the same manner as those in FIG. 22 are provided withthe same reference numerals.

In FIG. 26 , terminal 2202-2 is newly added. Terminal 2202-2 performsdirectivity control to generate reception directivity 2203-2, andreceives transmission beam 2201-1 of “(multicast) stream 1-1.”

Next, a description will be given with reference to FIG. 26 .

FIG. 26 illustrates the state in which terminal 2202-2 newlyparticipates in the multicast communication performed between basestation 700 and terminal 2202-1. Hereinafter, the state illustrated inFIG. 26 will be described as an example. As is understood, the basestation transmits the “terminal reception-directivity-control trainingsymbol” 2701 and the “data symbols” 2702 as illustrated in FIG. 27 , butdoes not transmit the “base-station transmission training symbol”illustrated in FIG. 24 . Note that, the horizontal axis represents thetime direction in FIG. 27 .

FIG. 28 illustrates an example of an operation performed by the basestation and the terminal in order to achieve the state as illustrated inFIG. 26 , that is, a state in which the base station transmits themulticast transmission beam to two terminals.

[28-1] Terminal 2202-2 makes a “request for multicast transmission ofstream 1” to the base station. The “request for multicast transmissionof stream 1” is transmitted in one of the unicast transmission sectionsillustrated in FIG. 25 .

[28-2] In response to the request indicated at above [28-1], the basestation indicates to terminal 2202-2 that “multicast stream 1 is beingtransmitted.” The indication “multicast stream 1 is being transmitted”is transmitted in one of the unicast transmission sections illustratedin FIG. 25 .

[28-3] In response to the indication indicated at above [28-2], terminal2202-2 performs reception directivity control in order to startreceiving multicast stream 1. Terminal 2202-2 performs the receptiondirectivity control and indicates to the base station that “multicaststream 1” has been received successfully.

[28-4] In response to the indication indicated at above [28-3], the basestation confirms that the terminal has successfully received “multicaststream 1.”

[28-5] Terminal 2202-2 performs the reception directivity control andstart receiving “multicast stream 1.”

FIG. 29 illustrates the state in which the base station illustrated inFIG. 22 is transmitting a multicast transmission stream to one terminaland to which one new terminal is added. Note that, components in FIG. 29that operate in the same manner as those in FIG. 22 are provided withthe same reference numerals.

In FIG. 29 , terminal 2202-2 is newly added. FIG. 29 differs from FIG.26 in that base station 700 newly transmits transmission beam 2201-2 of“(multicast) stream 1-2” (second transmission beam of stream 1), andterminal 2202-2 performs directivity control to generate receptiondirectivity 2203-2 and receive transmission beam 2201-2 of (multicast)stream 1-2.

Next, control performed by the base station and the terminal in order toachieve the state illustrated in FIG. 29 will be described.

FIG. 29 illustrates the state in which terminal 2202-2 newlyparticipates in the multicast communication performed between basestation 700 and terminal 2202-1. Hereinafter, the state illustrated inFIG. 29 will be described as an example.

FIG. 30 illustrates an example of an operation performed by the basestation and the terminal in order to achieve the state as illustrated inFIG. 29 , that is, a state in which the base station transmits themulticast transmission beams to two terminals.

[30-1] Terminal 2202-2 makes a “request for multicast transmission ofstream 1” to the base station. The “request for multicast transmissionof stream 1” is transmitted in one of the unicast transmission sectionsillustrated in FIG. 25 .

[30-2] In response to the request indicated at above [30-1], the basestation indicates to terminal 2202-2 that “multicast stream 1 is beingtransmitted.” The indication “multicast stream 1 is being transmitted”is transmitted in one of the unicast transmission sections illustratedin FIG. 25 .

[30-3] In response to the indication indicated at above [30-2], terminal2202-2 indicates to the base station that “multicast stream 1 has notbeen received.” The indication “multicast stream 1 has not beenreceived” is transmitted in one of the unicast transmission sectionsillustrated in FIG. 25 .

[30-4] In response to the indication indicated at above [30-3], the basestation determines to transmit another transmission beam of multicaststream 1 (i.e., transmission beam 2201-2 in FIG. 29 ). Note that,although another transmission beam of multicast stream 1 is heredetermined to be transmitted, the other transmission beam of multicaststream 1 may be determined not to be transmitted. A description will begiven below in this respect.

The base station then transmits to terminal 2202-2 a training symbol fortransmission directivity control and a training symbol for receptiondirectivity control in order to perform multicast transmission of stream1. Note that the base station transmits the transmission beam of stream1-1 in FIG. 29 in addition to the transmission of these symbols. Adescription will be given below in this respect.

[30-5] Terminal 2202-2 receives the training symbol for transmissiondirectivity control and the training symbol for reception directivitycontrol transmitted by the base station. Terminal 2202-2 then transmitsfeedback information to the base station in order for the base stationto perform the transmission directivity control and for terminal 2202-2to perform the reception directivity control.

[30-6] Based on the feedback information transmitted by terminal 2202-2,the base station determines a transmission directivity control method(for example, determines a weighting factor used for performingdirectivity control). Then, the base station transmits the data symbolsof stream 1 (transmission beam 2201-2 of stream 1-2 in FIG. 29 ).

[30-7] Terminal 2202-2 determines a reception directivity control method(for example, determines a weighting factor used for performingdirectivity control). Then, terminal 2202-2 starts receiving the datasymbols of stream 1 transmitted by the base station (transmission beam2201-2 of stream 1-2 in FIG. 29 ).

Note that the “procedure for performing communication between the basestation and the terminal” in FIG. 30 is an example, and the order oftransmissions of information is not limited to that of FIG. 30 . Forexample, it is possible to perform the same operation even when theorder of transmissions of information is changed.

In addition, although the example in which the terminal performs thereception directivity control has been described with reference to FIG.30 , the terminal does not have to perform the reception directivitycontrol. In this case, the base station does not have to transmit thetraining symbol for reception directivity control, and the terminal doesnot have to determine the reception directivity control method in FIG.30 .

In the case where the base station performs transmission directivitycontrol and the base station has the configuration of FIG. 1 ,multiplication factors of multipliers 204-1, 204-2, 204-3, and 204-4 inFIG. 2 may be set, for example. In the case where the base station hasthe configuration of FIG. 3 , a weighting factor of weighting-combiner301 may be set, for example. Note that, the number of streams to betransmitted is “2” in the case of FIG. 29 , but is not limited thereto.

In the case where terminals 2202-1 and 2202-2 perform receptiondirectivity control and each of the terminals has the configuration ofFIG. 4 , multiplication factors of multipliers 503-1, 503-2, 503-3, and503-4 in FIG. 5 may be set, for example. In the case where the terminalhas the configuration of FIG. 6 , multiplication factors of multipliers603-1, 603-2, . . . , and 603-L may be set, for example.

FIG. 31 illustrates an example of symbols transmitted by the basestation when the base station transmits data symbols of stream 1 afterthe communication between the base station and the terminal in FIG. 30is completed. In FIG. 31 , the horizontal axis represents the timedirection.

Since “stream 1-1” of FIG. 29 is present, there are “(multicast) stream1-1 data symbol (M)” 2501-1-M, “(multicast) stream 1-1 data symbol(M+1)” 2501-1-(M+1), and “(multicast) stream 1-1 data symbol (M+2)”2501-1-M+2 in FIG. 31 as in FIG. 25 . Note that, the reason for thedescription of “(M), (M+1), (M+2)” is because (multicast) stream 1-1exists before (multicast) stream 1-2 exists. Accordingly, M denotes aninteger equal to or greater than 2 in FIG. 31 .

As illustrated in FIG. 31 , there are “(multicast) stream 1-2 datasymbol (1)” 3101-1, “(multicast) stream 1-2 data symbol (2)” 3101-2, and“(multicast) stream 1-2 data symbol (3)” 3101-3 in a section other thanunicast transmission sections 2503-1 and 2503-2.

Similarly to the symbols described above, the symbols illustrated inFIG. 31 are configured as follows.

The “(multicast) stream 1-1 data symbol (M)” 2501-1-M, “(multicast)stream 1-1 data symbol (M+1)” 2501-1-(M+1), “(multicast) stream 1-1 datasymbol (M+2)” 2501-1-(M+2), “(multicast) stream 1-2 data symbol (1)”3101-1, “(multicast) stream 1-2 data symbol (2)” 3101-2, and“(multicast) stream 1-2 data symbol (3)” 3101-3 are data symbols fortransmitting “stream 1.”

The terminal obtains the “data symbols of stream 1-1” to obtain the“data of stream 1.” The terminal also obtains the “data symbols ofstream 1-2” to obtain the “data of stream 1.”

The directivities of the transmission beams of “(multicast) stream 1-1data symbol (M)” 2501-1-M, “(multicast) stream 1-1 data symbol (M+1)”2501-1-(M+1), “(multicast) stream 1-1 data symbol (M+2)” 2501-1-(M+2)are different from the directivities of the transmission beams of and“(multicast) stream 1-2 data symbol (1)” 3101-1, “(multicast) stream 1-2data symbol (2)” 3101-2, and “(multicast) stream 1-2 data symbol (3)”3101-3. Thus, a set of multiplication factors (or weighting factors) ofthe transmission apparatus of the base station used to generate thetransmission beams of “(multicast) stream 1-1 data symbol (M)” 2501-1-M,“(multicast) stream 1-1 data symbol (M+1)” 2501-1-(M+1), “(multicast)stream 1-1 data symbol (M+2)” 2501-1-(M+2) is different from a set ofmultiplication factors (or weighting factors) of the transmissionapparatus of the base station used to generate the transmission beams of“(multicast) stream 1-2 data symbol (1)” 3101-1, “(multicast) stream 1-2data symbol (2)” 3101-2, and “(multicast) stream 1-2 data symbol (3)”3101-3.

With the above configuration, two terminals can receive multicaststreams transmitted by the base station. At this time, the directivitycontrol is performed through transmission and reception, so that, as aneffect of the present embodiment, it is possible to broaden the area inwhich the multicast streams can be received. Moreover, the addition of astream and/or the addition of a transmission beam are adaptivelyperformed, so that, as an effect of the present embodiment, it ispossible to effectively utilize the frequency resource, time resource,and/or spatial resource for transmitting data.

Note that, such control as described below may also be performed.Details of the control are as follows.

FIG. 32 is an “example of symbols transmitted by a base station when thebase station transmits data symbols (of stream 1) after thecommunication between the base station and the terminal in FIG. 30 iscompleted,” which is an example different from that in FIG. 31 . In FIG.32 , the horizontal axis represents the time direction. Note that,components in FIG. 32 that operate in the same manner as those in FIG.25 or 31 are provided with the same reference numerals.

FIG. 32 differs from FIG. 31 in that unicast transmission sections2503-1 and 2503-2 are set longer in time, so that the base station doesnot transmit a further multicast symbol additionally.

FIG. 33 illustrates an example of an operation in which the base stationtransmits multicast transmission beams to two terminals (terminals2202-1 and 2202-2) as illustrated in FIG. 29 and, further, new terminal2202-3 requests, from the base station, addition of a transmission beam.Note that, the frame of a modulation signal transmitted by the basestation is illustrated in FIG. 32 .

[33-1] Terminal 2202-3 makes a “request for multicast transmission ofstream 1” to the base station. The “request for multicast transmissionof stream 1” is transmitted in one of the unicast transmission sectionsillustrated in FIG. 32 .

[33-2] In response to the request indicated at above [33-1], the basestation indicates to terminal 2202-3 that multicast stream 1 is beingtransmitted. The “indication of multicast stream 1 being transmitted” istransmitted in one of the unicast transmission sections illustrated inFIG. 32 .

[33-3] In response to the indication indicated at above [33-2], terminal2202-3 indicates to the base station that “multicast stream 1 has notbeen received.” The “indication that multicast stream 1 has not beenreceived” is transmitted in one of the unicast transmission sectionsillustrated in FIG. 32 .

[33-4] In response to the indication indicated at above [33-3], the basestation determines whether or not a transmission beam different from thetransmission beam of stream 1-1 and the transmission beam of stream 1-2can be transmitted as one of the transmission beams of multicast stream1. In this case, considering that the frame is as illustrated in FIG. 32, the base station determines not to transmit another transmission beamof multicast stream 1. Accordingly, the base station indicates toterminal 2202-3 that “another transmission beam of multicast stream 1 isnot transmitted.” Note that the “indication of not transmitting anothertransmission beam of multicast stream 1” is transmitted in one of theunicast transmission sections illustrated in FIG. 32 .

[33-5] Terminal 2202-3 receives the “indication of not transmittinganother transmission beam of multicast stream 1.”

Note that the “procedure for performing communication between the basestation and the terminal” in FIG. 33 is an example, and the order oftransmissions of information is not limited to that of FIG. 33 . Forexample, it is possible to perform the same operation even when theorder of transmissions is changed. As in this example, whencommunication resources for multicast transmission are insufficient,addition of a multicast transmission beam does not have to be performed.

FIG. 34 illustrates an example of an operation in which the base stationtransmits multicast transmission beams to two terminals (terminals2202-1 and 2202-2) as illustrated in FIG. 29 and, further, new terminal2202-3 requests, from the base station, addition of a transmission beamof another multicast stream (stream 2). Note that, the frame of amodulation signal transmitted by the base station is as illustrated inFIG. 31 .

[34-1] Terminal 2202-3 makes a “request for multicast transmission ofstream 2” to the base station. The “request for multicast transmissionof stream 2” is transmitted in one of unicast transmission sections 2503illustrated in FIG. 31 .

[34-2] In response to the request indicated at above [34-1], the basestation indicates to terminal 2202-3 that “multicast stream 2 is notbeing transmitted.” In addition, the base station determines whether ornot the base station can additionally transmit a transmission beam ofmulticast stream 2. In this case, considering the frame state asillustrated in FIG. 31 , the base station indicates to terminal 2202-3the “support for transmission of the transmission beam of multicaststream 2.” The “indication that multicast stream 2 is not beingtransmitted” and the “indication that multicast stream 2 can betransmitted” are transmitted in one of unicast transmission sections2503 illustrated in FIG. 31 .

[34-3] In response to the indication indicated at above [34-2], terminal2203-3 indicates to the base station “completion of preparation forreceiving multicast stream 2.” The indication of the “completion ofpreparation for receiving multicast stream 2” is transmitted in one ofunicast transmission sections 2503 illustrated in FIG. 31 .

[34-4] In response to the indication indicated at above [34-3], the basestation determines to transmit the transmission beam of multicast stream2. The base station then transmits to terminal 2202-3 a training symbolfor transmission directivity control and a training symbol for receptiondirectivity control in order to perform multicast transmission of stream2. Note that the base station transmits the transmission beam of stream1-1 and the transmission beam of stream 1-2 as in FIG. 31 , separatelyfrom the transmission of the training symbols. A description will begiven below in this respect.

[34-5] Terminal 2202-3 receives the training symbol for transmissiondirectivity control and the training symbol for reception directivitycontrol transmitted by the base station. Terminal 2202-3 then transmitsfeedback information to the base station in order for the base stationto perform the transmission directivity control and for terminal 2202-3to perform the reception directivity control.

[34-6] Based on the feedback information transmitted by terminal 2202-3,the base station determines a transmission directivity control method(for example, determines a weighting factor used for performingdirectivity control) and transmits data symbols of stream 2.

[34-7] Terminal 2202-3 determines a reception directivity control method(for example, determines a weighting factor used for performingdirectivity control) and starts receiving the data symbols of stream 2transmitted by the base station.

Note that the “procedure for performing communication between the basestation and the terminal” in FIG. 34 is an example, and the order oftransmissions of information is not limited to that of FIG. 34 . Forexample, it is possible to perform the same operation even when theorder of transmissions of information is changed.

In addition, although the example in which the terminal performs thereception directivity control has been described with reference to FIG.34 , the terminal does not have to perform the reception directivitycontrol. In this case, the base station does not have to transmit thetraining symbol for reception directivity control, and the terminal doesnot have to determine the reception directivity control method in FIG.34 .

In the case where the base station performs transmission directivitycontrol and the base station has the configuration of FIG. 1 ,multiplication factors of multipliers 204-1, 204-2, 204-3, and 204-4 inFIG. 2 may be set, for example.

In the case where terminals 2202-1, 2202-2, and 2202-3 perform receptiondirectivity control and the terminal has the configuration of FIG. 4 ,multiplication factors of multipliers 503-1, 503-2, 503-3, and 503-4 inFIG. 5 may be set, for example. In the case where the terminal has theconfiguration of FIG. 6 , multiplication factors of multipliers 603-1,603-2, . . . , and 603-L may be set, for example.

FIG. 35 is an example of symbols transmitted by the base station whenthe base station transmits the data symbols of stream 1 and stream 2after the communication between the base station and the terminal inFIG. 34 is completed. In FIG. 35 , the horizontal axis represents thetime direction.

Since “stream 1-1” and “stream 1-2” illustrated in FIG. 31 exist, thereare “(multicast) stream 1-1 data symbol (M)” 2501-1-M, “(multicast)stream 1-1 data symbol (M+1)” 2501-1-(M+1), and “(multicast) stream 1-1data symbol (M+2)” 2501-1-(M+2) in FIG. 35 . Further, there are“(multicast) stream 1-2 data symbol (N)” 3101-N, “(multicast) stream 1-2data symbol (N+1)” 3101-(N+1), and “(multicast) stream 1-2 data symbol(N+2)” 3101-(N+2). Note that, N and M are an integer equal to or greaterthan 2.

As illustrated in FIG. 35 , there are “(multicast) stream 2-1 datasymbol (1)” 3501-1, “(multicast) stream 2-1 data symbol (2)” 3501-2, and“(multicast) stream 2-1 data symbol (3)” 3501-3 in sections other thanunicast transmission sections 2503-1 and 2503-2.

Similarly to the symbols described above, the symbols illustrated inFIG. 35 are configured as follows.

-   -   The “(multicast) stream 1-1 data symbol (M)” 2501-1-M,        “(multicast) stream 1-1 data symbol (M+1)” 2501-1-(M+1),        “(multicast) stream 1-1 data symbol (M+2)” 2501-1-(M+2),        “(multicast) stream 1-2 data symbol (N)” 3101-N, “(multicast)        stream 1-2 data symbol (N+1)” 3101-(N+1), and “(multicast)        stream 1-2 data symbol (N+2)” 3101-(N+2) are data symbols for        transmitting “stream 1.”    -   The terminal obtains the “data symbols of stream 1-1” to obtain        the “data of stream 1.” The terminal also obtains the “data        symbols of stream 1-2” to obtain the “data of stream 1.”    -   The directivities of the transmission beams of “(multicast)        stream 1-1 data symbol (M)” 2501-1-M, “(multicast) stream 1-1        data symbol (M+1)” 2501-1-(M+1), “(multi ca st) stream 1-1 data        symbol (M+2)” 2501-1-(M+2) are different from the directivities        of the transmission beams of and “(multicast) stream 1-2 data        symbol (1)” 3101-1, “(multicast) stream 1-2 data symbol (2)”        3101-2, and “(multicast) stream 1-2 data symbol (3)” 3101-3.        Thus, a set of multiplication factors (or weighting factors) of        the transmission apparatus of the base station used to generate        the transmission beams of “(multicast) stream 1-1 data symbol        (M)” 2501-1-M, “(multicast) stream 1-1 data symbol (M+1)”        2501-1-(M+1), “(multicast) stream 1-1 data symbol (M+2)”        2501-1-(M+2) is different from a set of multiplication factors        (or weighting factors) of the transmission apparatus of the base        station used to generate the transmission beams of “(multicast)        stream 1-2 data symbol (1)” 3101-1, “(multicast) stream 1-2 data        symbol (2)” 3101-2, and “(multicast) stream 1-2 data symbol (3)”        3101-3.    -   The “(multicast) stream 2-1 data symbol (1)” 3501-1,        “(multicast) stream 2-1 data symbol (2)” 3501-2, and        “(multicast) stream 2-1 data symbol (3)” 3501-3 are data symbols        for transmitting “stream 2.”    -   The terminal obtains the data symbols of stream 2-1 to obtain        the data of stream 2.

With the above configuration, the terminal can receive a plurality ofmulticast streams (stream 1 and stream 2) transmitted by the basestation. At this time, the directivity control is performed throughtransmission and reception, so that, as an effect of the presentembodiment, it is possible to broaden the area in which the multicaststreams can be received. Moreover, the addition of a stream and/or theaddition of a transmission beam are adaptively performed, so that, as aneffect of the present embodiment, it is possible to effectively utilizethe frequency resource, time resource, and/or spatial resource fortransmitting data.

Note that, such control as described below may also be performed.Details of the control are as follows.

FIG. 32 is the “example of symbols transmitted by a base station whenthe base station transmits data symbols (of stream 1),” which is anexample different from that in FIG. 35 . In FIG. 32 , the horizontalaxis represents the time direction. Note that, components in FIG. 32that operate in the same manner as those in FIG. 25 or 31 are providedwith the same reference numerals.

FIG. 32 differs from FIG. 35 in that unicast transmission sections2503-1 and 2503-2 are set longer in time, so that the base station doesnot add and transmit a further multicast symbol (e.g., a symbol of a newstream).

FIG. 36 illustrates an example of an operation in which the base stationtransmits multicast transmission beams to two terminals (terminals2202-1 and 2202-2) as illustrated in FIG. 29 and, further, new terminal2202-3 requests, from the base station, addition of a transmission beamof another multicast stream (stream 2). Note that, the frame of amodulation signal transmitted by the base station is illustrated in FIG.32 .

[36-1] Terminal 2202-3 makes a “request for multicast transmission ofstream 2” to the base station. The “request for multicast transmissionof stream 2” is transmitted in one of the unicast transmission sectionsillustrated in FIG. 32 .

[36-2] In response to the request indicated at above [36-1], the basestation indicates to terminal 2202-3 that “multicast stream 2 is notbeing transmitted.” The indication “multicast stream 2 is not beingtransmitted” is transmitted in one of the unicast transmission sectionsillustrated in FIG. 32 . In addition, the base station determineswhether or not the transmission beam of multicast stream 2 can betransmitted. Considering the frame illustrated in FIG. 32 , the basestation determines not to transmit the transmission beam of multicaststream 2. Accordingly, the base station indicates to terminal 2202-3that “the transmission beam of multicast stream 2 is not transmitted.”Note that, the “indication of not transmitting the transmission beam ofmulticast stream 2” is transmitted in one of the unicast transmissionsections illustrated in FIG. 32 .

[36-3] Terminal 2202-3 receives the “indication of not transmitting thetransmission beam of multicast stream 2.”

Note that the “procedure for performing communication between the basestation and the terminal” in FIG. 36 is an example, and the order oftransmissions of information is not limited to that of FIG. 36 . Forexample, it is possible to perform the same operation even when theprocedure of transmissions is changed. As in this example, whencommunication resources for multicast transmission are insufficient,addition of a stream and/or addition of a multicast transmission beam donot have to be performed.

Note that, a supplementary description will be given of a method ofsetting unicast transmission sections 2503-1 and 2503-2 illustrated inFIG. 35 and the like.

For example, in FIG. 35 , the maximum number of multicast transmissionbeams is determined or set in advance.

Then, in response to requests by terminals, the base station transmitsmulticast transmission beams, the number of which is equal to or lessthan the maximum number of multicast transmission beams. For example, inthe case of FIG. 35 , the number of multicast transmission beams is 3.Then, the base station transmits a plurality of multicast transmissionbeams, and determines, as a unicast transmission section, a temporallyidle time after the transmission of each of the plurality oftransmission beams.

The unicast transmission sections may be defined as described above.

(Supplement 1)

Supplement 1 describes a case where the base station performs unicastcommunication (that is, specific communication) with a plurality ofterminals.

For example, #1 symbol group 901-1 of stream 1, #2 symbol group 901-2 ofstream 1, and #3 symbol group 901-3 of stream 1 in FIG. 9 may be controlinformation broadcast by the base station to a plurality of terminals inorder for the base station to perform data communication with theplurality of terminals. That is, these symbol groups may be informationon a broadcast channel. Note that, the control information isinformation that can be used, for example, to realize data communicationbetween the base station and the terminal.

For example, #1 symbol group 901-1 of stream 1, #2 symbol group 901-2 ofstream 1, and #3 symbol group 901-3 of stream 1 in FIG. 9 may be commonsearch spaces. Note that the common search spaces are controlinformation for performing cell control. Note also that the commonsearch spaces are control information to be broadcast to a plurality ofterminals.

For example, #1 symbol group 902-1 of stream 2, #2 symbol group 902-2 ofstream 2, and #3 symbol group 902-3 of stream 2 in FIG. 9 may be controlinformation broadcast by the base station to a plurality of terminals inorder for the base station to perform data communication with theplurality of terminals. That is, these symbol groups may be broadcastchannel information.

For example, #1 symbol group 902-1 of stream 2, #2 symbol group 902-2 ofstream 2, and #3 symbol group 902-3 of stream 2 in FIG. 9 may be commonsearch spaces.

The #1 symbol group 901-1 of stream 1, #2 symbol group 901-2 of stream1, and #3 symbol group 901-3 of stream 1, #1 symbol group 902-1 ofstream 2, #2 symbol group 902-2 of stream 2, and #3 symbol group 902-3of stream 2 in FIG. 9 are the same as those described in relation to theprevious embodiments and, therefore, the descriptions thereof areomitted.

For example, #1 symbol group 1401-1 of modulation signal 1, #2 symbolgroup 1401-2 of modulation signal 1, and #3 symbol group 1401-3 ofmodulation signal 1 in FIG. 14 may be control information broadcast bythe base station to a plurality of terminals in order for the basestation to perform data communication with the plurality of terminals.That is, these symbol groups may be broadcast channel information.

For example, #1 symbol group 1401-1 of modulation signal 1, #2 symbolgroup 1401-2 of modulation signal 1, and #3 symbol group 1401-3 ofmodulation signal 1 in FIG. 14 may be common search spaces.

For example, #1 symbol group 1402-1 of modulation signal 2, #2 symbolgroup 1402-2 of modulation signal 2, and #3 symbol group 1402-3 ofmodulation signal 2 in FIG. 14 may be control information broadcast bythe base station to a plurality of terminals in order for the basestation to perform data communication with the plurality of terminals.That is, these symbol groups may be broadcast channel information.

For example, #1 symbol group 1402-1 of modulation signal 2, #2 symbolgroup 1402-2 of modulation signal 2, and #3 symbol group 1402-3 ofmodulation signal 2 in FIG. 14 may be common search spaces.

The #1 symbol group 1401-1 of modulation signal 1, #2 symbol group1401-2 of modulation signal 1, and #3 symbol group 1401-3 of modulationsignal 1 in FIG. 14 are as described in relation to the previousembodiments. The #1 symbol group 1402-1 of modulation signal 2, #2symbol group 1402-2 of modulation signal 2, and #3 symbol group 1402-3of modulation signal 2 in FIG. 14 are as described in relation to theprevious embodiments.

For example, stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol(2) 2501-1-2, and stream 1-1 data symbol (3) 2501-1-3 in FIG. 25 may becontrol information broadcast by the base station to a plurality ofterminals in order for the base station to perform data communicationwith the plurality of terminals. That is, these symbols may be broadcastchannel information.

For example, stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol(2) 2501-1-2, and stream 1-1 data symbol (3) 2501-1-3 in FIG. 25 may becommon search spaces.

Note that, stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol(2) 2501-1-2, and stream 1-1 data symbol (3) 2501-1-3 in FIG. 25 are asdescribed in relation to the previous embodiments.

For example, stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2) 2501-1-(M+2), stream1-2 data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, andstream 1-2 data symbol (3) 3101-3 in FIGS. 31 and 32 may be controlinformation broadcast by the base station to a plurality terminals inorder for the base station to perform data communication with theplurality of terminals. That is, these symbols may be broadcast channelinformation.

For example, stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2) 2501-1-(M+2), stream1-2 data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, andstream 1-2 data symbol (3) 3101-3 in FIGS. 31 and 32 may be commonsearch spaces.

Note that stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2) 2501-1-(M+2), stream1-2 data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, andstream 1-2 data symbol (3) 3101-3 in FIGS. 31 and 32 are as described inrelation to the previous embodiments.

For example, in FIG. 35 , stream 1-1 data symbol (M) 2501-1-M, stream1-1 data symbol (M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2)2501-1-(M+2), stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol(N+1) 3101-(N+1), and stream 1-2 data symbol (N+2) 3101-(N+2) may becontrol information broadcast by the base station to a plurality ofterminals in order for the base station to perform data communicationwith the plurality of terminals. That is, these symbols may be broadcastchannel information.

For example, in FIG. 35 , stream 1-1 data symbol (M) 2501-1-M, stream1-1 data symbol (M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2)2501-1-(M+2), stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol(N+1) 3101-(N+1), and stream 1-2 data symbol (N+2) 3101-(N+2) may becommon search spaces.

For example, stream 2-1 data symbol (1) 3501-1, stream 2-1 data symbol(2) 3501-2, and stream 2-1 data symbol (3) 3501-3 in FIG. 35 may becontrol information broadcast by the base station to a plurality ofterminals in order for the base station to perform data communicationwith the plurality of terminals. That is, these symbols may be broadcastchannel information.

For example, stream 2-1 data symbol (1) 3501-1, stream 2-1 data symbol(2) 3501-2, and stream 2-1 data symbol (3) 3501-3 in FIG. 35 may becommon search spaces.

Note that, in FIG. 35 , stream 1-1 data symbol (M) 2501-1-M, stream 1-1data symbol (M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2)2501-1-(M+2), stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol(N+1) 3101-(N+1), and stream 1-2 data symbol (N+2) 3101-(N+2) are asdescribed in relation to the previous embodiments. The stream 2-1 datasymbol (1) 3501-1, stream 2-1 data symbol (2) 3501-2, and stream 2-1data symbol (3) 3501-3 in FIG. 35 are as described in relation to theprevious embodiments.

In FIGS. 9, 14, 25, 31, 32, and 35 , a single-carrier transmissionmethod or a multi-carrier transmission scheme such as OFDM may be usedfor transmission of data symbols. In addition, the temporal positions ofthe data symbols are not limited to those illustrated in FIGS. 9, 14,25, 31, 32, and 35 .

Although the descriptions with reference to FIGS. 25, 31, 32, and 35have been given in which the horizontal axis represents the timedirection, the same implementation is possible even when the horizontalaxis represents a frequency (carrier) direction. Note that, when thehorizontal axis represents the frequency (carrier) direction, the basestation transmits each of the data symbols using one or more carriers orsubcarriers.

(Supplement 2)

Supplement 2 describes a case where the base station performs unicastcommunication (that is, specific communication) with a plurality ofterminals.

For example, #1 symbol group 901-1 of stream 1, #2 symbol group 901-2 ofstream 1, #3 symbol group 901-3 of stream 1, #1 symbol group 902-1 ofstream 2, #2 symbol group 902-2 of stream 2, and #3 symbol group 902-3of stream 2 in FIG. 9 may be data to a base station or may be dataaddressed to any of a plurality of terminals performing communication.In this case, control information may be included in the data.

Note that, #1 symbol group 901-1 of stream 1, #2 symbol group 901-2 ofstream 1, #3 symbol group 901-3 of stream 1, #1 symbol group 902-1 ofstream 2, #2 symbol group 902-2 of stream 2, and #3 symbol group 902-3of stream 2 in FIG. 9 are as described in relation to the previousembodiments.

For example, #1 symbol group 1401-1 of modulation signal 1, #2 symbolgroup 1401-2 of modulation signal 1, #3 symbol group 1401-3 ofmodulation signal 1, #1 symbol group 1402-1 of modulation signal 2, #2symbol group 1402-2 of modulation signal 2, and #3 symbol group 1402-3of modulation signal 2 in FIG. 14 may be data addressed to the basestation or may be data addressed to any of the plurality of terminalsperforming communication. In this case, control information may beincluded in the data.

Note that, #1 symbol group 1401-1 of modulation signal 1, #2 symbolgroup 1401-2 of modulation signal 1, #3 symbol group 1401-3 ofmodulation signal 1, #1 symbol group 1402-1 of modulation signal 2, #2symbol group 1402-2 of modulation signal 2, and #3 symbol group 1402-3of modulation signal 2 in FIG. 14 are as described in relation to theprevious embodiments.

For example, stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol(2) 2501-1-2, and stream 1-1 data symbol (3) 2501-1-3 in FIG. 25 may bedata to the base station or may be data addressed to any of theplurality of terminals performing communication. In this case, controlinformation may be included in the data.

Note that, stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol(2) 2501-1-2, and stream 1-1 data symbol (3) 2501-1-3 in FIG. 25 are asdescribed in relation to the previous embodiments.

For example, stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2) 2501-1-(M+2), stream1-2 data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, andstream 1-2 data symbol (3) 3101-3 in FIGS. 31 and 32 may be dataaddressed to the base station or may be data addressed to any of theplurality of terminals performing communication. In this case, controlinformation may be included in the data.

Note that, stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2) 2501-1-(M+2), stream1-2 data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, andstream 1-2 data symbol (3) 3101-3 in FIGS. 31 and 32 are as described inrelation to the previous embodiments.

For example, in FIG. 35 , stream 1-1 data symbol (M) 2501-1-M, stream1-1 data symbol (M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2)2501-1-(M+2), stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol(N+1) 3101-(N+1), and stream 1-2 data symbol (N+2) 3101-(N+2) may bedata addressed to the base station or may be data addressed to any ofthe plurality of terminals performing communication. In this case,control information may be included in the data.

For example, stream 2-1 data symbol (1) 3501-1, stream 2-1 data symbol(2) 3501-2, and stream 2-1 data symbol (3) 3501-3 in FIG. 35 may be dataaddressed to the base station or may be data addressed to any of theplurality of terminals performing communication. In this case, controlinformation may be included in the data.

Note that, in FIG. 35 , stream 1-1 data symbol (M) 2501-1-M, stream 1-1data symbol (M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2)2501-1-(M+2), stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol(N+1) 3101-N+1, stream 1-2 data symbol (N+2) 3101-N+2, stream 2-1 datasymbol (1) 3501-1, stream 2-1 data symbol (2) 3501-2, and stream 2-1data symbol (3) 3501-3 are as described in relation to the previousembodiments.

In FIGS. 9, 14, 25, 31, 32, and 35 , a single-carrier transmissionmethod or a multi-carrier transmission scheme such as OFDM may be usedfor transmission of data symbols. In addition, the temporal positions ofthe data symbols are not limited to those illustrated in FIGS. 9, 14,25, 31, 32, and 35 .

Although the descriptions with reference to FIGS. 25, 31, 32, and 35have been given in which the horizontal axis represents the timedirection, the same implementation is possible even when the horizontalaxis represents a frequency (carrier) direction. Note that, when thehorizontal axis represents the frequency (carrier) direction, the basestation transmits each of the data symbols using one or more carriers orsubcarriers.

(Supplement 3)

The base station may transmit another symbol group using anothertransmission beam different from “the transmission beam of #1 symbolgroup 901-1 of stream 1, the transmission beam of #2 symbol group 901-2of stream 1, the transmission beam of #3 symbol group 901-3 of stream 1,the transmission beam of #1 symbol group 902-1 of stream 2, thetransmission beam of #2 symbol group 902-2 of stream 2, or thetransmission beam of #3 symbol group 902-3 of stream 2” during a timeperiod of transmitting #1 symbol group 901-1 of stream 1, #2 symbolgroup 901-2 of stream 1, #3 symbol group 901-3 of stream 1, #1 symbolgroup 902-1 of stream 2, #2 symbol group 902-2 of stream 2, or #3 symbolgroup 902-3 of stream 2 as in the frame configuration of FIG. 9 .

In addition, the base station of FIG. 3 may generate a transmission beamfor the above-described “other symbol group” through the “signalprocessing by signal processor 102 and the signal processing byweighting combiner 301” or through the “signal processing by signalprocessor 102 or the signal processing by weighting combiner 301.”

The base station may also transmit another symbol group using anothertransmission beam different from “the transmission beam of #1 symbolgroup 1401-1 of modulation signal 1, the transmission beam of #2 symbolgroup 1401-2 of modulation signal 1, the transmission beam of #3 symbolgroup 1401-3 of modulation signal 1, the transmission beam of #1 symbolgroup 1402-1 of modulation signal 2, the transmission beam of #2 symbolgroup 1402-2 of modulation signal 2, or the transmission beam of #3symbol group 1402-3 of modulation signal 2” during a time period oftransmitting #1 symbol group 1401-1 of modulation signal 1, #2 symbolgroup 1401-2 of modulation signal 1, #3 symbol group 1401-3 ofmodulation signal 1, #1 symbol group 1402-1 of modulation signal 2, #2symbol group 1402-2 of modulation signal 2, or #3 symbol group 1402-3 ofmodulation signal 2 as in the frame configuration of FIG. 14 .

In this case, the “other symbol group” may be a symbol group includingdata symbols addressed to a certain terminal, a symbol group including acontrol information symbol group as described in other portions of thepresent disclosure, or a symbol group including other multicast datasymbols.

In addition, the base station of FIG. 3 may generate a transmission beamfor the above-described “other symbol group” through the “signalprocessing by signal processor 102 and the signal processing byweighting combiner 301” or through the “signal processing by signalprocessor 102 or the signal processing by weighting combiner 301.”

(Supplement 4)

For example, the base station may transmit another symbol group usinganother transmission beam different from the “transmission beam fortransmitting stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol(2) 2501-1-2, or stream 1-1 data symbol (3) 2501-1-3” during a timeperiod of transmitting stream 1-1 data symbol (1) 2501-1-1, stream 1-1data symbol (2) 2501-1-2, or stream 1-1 data symbol (3) 2501-1-3 as inthe frame configuration of FIG. 25 .

Note that, the same applies to the case where the horizontal axisrepresents the frequency direction in FIG. 25 . For example, the basestation may transmit another symbol group using another transmissionbeam different from the “transmission beam for transmitting stream 1-1data symbol (1) 2501-1-1, stream 1-1 data symbol (2) 2501-1-2, or stream1-1 data symbol (3) 2501-1-3” during a time period of transmittingstream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol (2)2501-1-2, or stream 1-1 data symbol (3) 2501-1-3.

For example, the base station may transmit another symbol group usinganother transmission beam different from the “transmission beam fortransmitting stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-(M+1), or stream 1-1 data symbol (M+2) 2501-1-(M+2)” duringa time period of transmitting stream 1-1 data symbol (M) 2501-1-M,stream 1-1 data symbol (M+1) 2501-1-(M+1), or stream 1-1 data symbol(M+2) 2501-1-(M+2) as in the frame configuration of FIGS. 31 and 32 .

Note that, the same applies to the case where the horizontal axisrepresents the frequency direction in FIGS. 31 and 32 . For example, thebase station may transmit another symbol group using anothertransmission beam different from the “transmission beam for transmittingstream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol (M+1)2501-1-(M+1), or stream 1-1 data symbol (M+2) 2501-1-(M+2)” during atime period of transmitting stream 1-1 data symbol (M) 2501-1-M, stream1-1 data symbol (M+1) 2501-1-(M+1), or stream 1-1 data symbol (M+2)2501-1-(M+2).

For example, the base station may transmit another symbol group usinganother transmission beam different from the “transmission beam fortransmitting stream 1-2 data symbol (1) 3101-1, stream 1-2 data symbol(2) 3101-2, or stream 1-2 data symbol (3) 3101-3” during a time periodof transmitting stream 1-2 data symbol (1) 3101-1, stream 1-2 datasymbol (2) 3101-2, or stream 1-2 data symbol (3) 3101-3 as in the frameconfiguration of FIGS. 31 and 32 .

Note that, the same applies to the case where the horizontal axisrepresents the frequency direction in FIGS. 31 and 32 . For example, thebase station may transmit another symbol group using anothertransmission beam different from the “transmission beam for transmittingstream 1-2 data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, orstream 1-2 data symbol (3) 3101-3” during a time period of transmittingstream 1-2 data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, orstream 1-2 data symbol (3) 3101-3.

For example, the base station may transmit another symbol group usinganother transmission beam different from the “transmission beam fortransmitting stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-(M+1), or stream 1-1 data symbol (M+2) 2501-1-(M+2)” duringa time period of transmitting stream 1-1 data symbol (M) 2501-1-M,stream 1-1 data symbol (M+1) 2501-1-(M+1), or stream 1-1 data symbol(M+2) 2501-1-(M+2) as in the frame configuration of FIG. 35 .

Note that, the same applies to the case where the horizontal axisrepresents the frequency direction in FIG. 35 . For example, the basestation may transmit another symbol group using another transmissionbeam different from the “transmission beam for transmitting stream 1-1data symbol (M) 2501-1-M, stream 1-1 data symbol (M+1) 2501-1-(M+1), orstream 1-1 data symbol (M+2) 2501-1-(M+2)” during a time period oftransmitting stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-(M+1), or stream 1-1 data symbol (M+2) 2501-1-(M+2).

For example, the base station may transmit another symbol group usinganother transmission beam different from the “transmission beam fortransmitting stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol(N+1) 3101-(N+1), or stream 1-2 data symbol (N+2) 3101-(N+2)” during atime period of transmitting stream 1-2 data symbol (N) 3101-N, stream1-2 data symbol (N+1) 3101-(N+1), or stream 1-2 data symbol (N+2)3101-(N+2) as in the frame configuration of FIG. 35 .

Note that, the same applies to the case where the horizontal axisrepresents the frequency direction in FIG. 35 . For example, the basestation may transmit another symbol group using another transmissionbeam different from the “transmission beam for transmitting stream 1-2data symbol (N) 3101-N, stream 1-2 data symbol (N+1) 3101-(N+1), orstream 1-2 data symbol (N+2) 3101-(N+2)” during a time period oftransmitting stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol(N+1) 3101-(N+1), or stream 1-2 data symbol (N+2) 3101-(N+2).

For example, the base station may transmit another symbol group usinganother transmission beam different from the “transmission beam fortransmitting stream 2-1 data symbol (1) 3501-1, stream 2-1 data symbol(2) 3501-2, or stream 2-1 data symbol (3) 3501-3” during a time periodof transmitting stream 2-1 data symbol (1) 3501-1, stream 2-1 datasymbol (2) 3501-2, or stream 2-1 data symbol (3) 3501-3 as in the frameconfiguration of FIG. 35 .

Note that, the same applies to the case where the horizontal axisrepresents the frequency direction in FIG. 35 . For example, the basestation may transmit another symbol group using another transmissionbeam different from the “transmission beam for transmitting stream 2-1data symbol (1) 3501-1, stream 2-1 data symbol (2) 3501-2, or stream 2-1data symbol (3) 3501-3” during a time period of transmitting stream 2-1data symbol (1) 3501-1, stream 2-1 data symbol (2) 3501-2, or stream 2-1data symbol (3) 3501-3.

In the above description, the “other symbol group” may be a symbol groupincluding data symbols addressed to a certain terminal, a symbol groupincluding a control information symbol group as described in otherportions of the present specification, or a symbol group including othermulticast data symbols.

In this case, the base station of FIG. 1 may generate a transmissionbeam for the above-described “other symbol group” through the signalprocessing by signal processor 102. Alternatively, the base station ofFIG. 1 may generate the transmission beam for the above-described “othersymbol group” by selecting one of antenna sections 106-1 to 106-M.

In addition, the base station of FIG. 3 may generate a transmission beamfor the above-described “other symbol group” through the “signalprocessing by signal processor 102 and the signal processing byweighting combiner 301” or through the “signal processing by signalprocessor 102 or the signal processing by weighting combiner 301.”

In addition, unicast transmission sections 2503-1 and 2503-2 asdescribed in FIGS. 25, 31, 32, and 35 do not have to be set.

(Supplement 5)

The descriptions in relation to FIGS. 31 and 32 are as follows.

-   -   The “(multicast) stream 1-1 data symbol (M)” 2501-1-M,        “(multicast) stream 1-1 data symbol (M+1)” 2501-1-(M+1),        “(multicast) stream 1-1 data symbol (M+2)” 2501-1-(M+2),        “(multicast) stream 1-2 data symbol (1)” 3101-1, “(multicast)        stream 1-2 data symbol (2)” 3101-2, and “(multicast) 1-2 data        symbol (3)” 3101-3 are data symbols for transmitting “stream 1.”    -   The terminal obtains the “data symbols of stream 1-1” to obtain        the “data of stream 1.” The terminal also obtains the “data        symbols of stream 1-2” to obtain the “data of stream 1.”

In addition, the description in relation to FIG. 35 is as follows.

-   -   The “(multicast) stream 1-1 data symbol (M)” 2501-1-M,        “(multicast) stream 1-1 data symbol (M+1)” 2501-1-(M+1),        “(multicast) stream 1-1 data symbol (M+2)” 2501-1-(M+2),        “(multicast) stream 1-2 data symbol (N)” 3101-N, “(multicast)        stream 1-2 data symbol (N+1)” 3101-(N+1), and “(multicast)        stream 1-2 data symbol (N+2)” 3101-(N+2) are data symbols for        transmitting “stream 1.”    -   The terminal obtains the “data symbols of stream 1-1” to obtain        the “data of stream 1.” The terminal also obtains the “data        symbols of stream 1-2” to obtain the “data of stream 1.”

In the following, a supplementary description will be given of theabove-mentioned contents. For example, in FIG. 35 , the above can berealized through following <method 1-1>, <method 1-2>, <method 2-1>, or<method 2-2>.

<Method 1-1>

-   -   Stream 1-1 data symbol (M) 2501-1-M and stream 1-2 data        symbol (N) 3101-N contain the same data. Stream 1-1 data symbol        (M+1) 2501-1-(M+1) and stream 1-2 data symbol (N+1) 3101-(N+1)        contain the same data. Stream 1-1 data symbol (M+2) 2501-1-(M+2)        and stream 1-2 data symbol (N+2) 3101-(N+2) contain the same        data.

<Method 1-2>

-   -   Stream 1-2 data symbol (L) 3101-L containing the same data as        the data contained in stream 1-1 data symbol (K) 2501-1-K is        present. Note that, “K” and “L” are integers.

<Method 2-1>

-   -   Data contained in stream 1-1 data symbol (M) 2501-1-M is partly        the same as data contained in stream 1-2 data symbol (N) 3101-N.        Data contained in stream 1-1 data symbol (M+1) 2501-1-(M+1) is        partly the same as data contained in stream 1-2 data symbol        (N+1) 3101-(N+1). Data contained in stream 1-1 data symbol (M+2)        2501-1-(M+2) is partly the same as data contained in stream 1-2        data symbol (N+2) 3101-(N+2).

<Method 2-2>

-   -   Stream 1-2 data symbol (L) 3101-L containing part of the data        contained in stream 1-1 data symbol (K) 2501-1-K is present.        Note that, “K” and “L” are integers.

That is, a first base station or a first transmission system generates afirst packet group including data of a first stream and a second packetgroup including data of the first stream, transmits a packet included inthe first packet group in a first period using a first transmissionbeam, and transmits a packet included in the second packet group in asecond period using a second transmission beam different from the firsttransmission beam, and the first period and the second period do notoverlap with each other.

Here, the second packet group may include a second packet including datathe same as data contained in a first packet included in the firstpacket group. Alternatively, as another configuration different from theabove, the second packet group may include a third packet including datathe same as a part of data contained in the first packet included in thefirst packet group.

Further, the first transmission beam and the second transmission beammay be transmission beams transmitted using the same antenna section andhaving directivities different from each other, or may be transmissionbeams transmitted using antenna sections different from each other.

In addition to the configuration of the first base station or the firsttransmission system, a second base station or a second transmissionsystem further generates a third packet group including data of thefirst stream, and transmits a packet included in the third packet groupin a third period using a third transmission beam different from thefirst transmission beam and the second transmission beam, and the thirdperiod does not overlap with the first period and the second period.

Here, the second base station or the second transmission system mayrepeatedly set the first period, the second period, and the third periodin a predetermined order.

In addition to the configuration of the first base station or the firsttransmission system, a third base station or a third transmission systemfurther generates a third packet group including data of the firststream, and transmits a packet included in the third packet group in athird period using a third transmission beam different from the firsttransmission beam and the second transmission beam, and at least part ofthe third period overlaps with the first period.

Here, the third base station or the third transmission system mayrepeatedly set the first period, the second period, and the thirdperiod, and a plurality of the third periods repeatedly set each may atleast partly overlap with the first period, or none of the plurality ofthird periods repeatedly set may overlap with the first period.

Further, in addition to the configuration of the first base station orthe first transmission system, a fourth base station or a fourthtransmission system further generates a fourth packet including data ofa second stream, and transmits the fourth packet in a fourth periodusing a fourth transmission beam different from the first transmissionbeam, and at least part of the fourth period overlaps with the firstperiod.

Note that, although the first period and the second period do notoverlap with each other in the above description, the first period andthe second period may partly overlap with each other, an entirety of thefirst period may overlap with the second period, or the entirety of thefirst period may overlap with an entirety of the second period.

Further, a fifth base station or a fifth transmission system maygenerate one or more packet groups including data of the first stream,transmit the one or more packet groups using transmission beamsdifferent between the one or more packet groups, and increase ordecrease, based on a signal transmitted from a terminal, the number ofpacket groups generated.

Note that although “stream 1-1 data symbol (M) 2501-1-M, stream 1-1 datasymbol (M+1) 2501-1-(M+1), stream 1-1 data symbol (M+2) 2501-1-(M+2),stream 1-2 data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2,and stream 1-2 data symbol (3) 3101-3” in FIGS. 31 and 32 and “stream1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol (M+1) 2501-1-(M+1),stream 1-1 data symbol (M+2) 2501-1-(M+2), stream 1-2 data symbol (N)3101-N, stream 1-2 data symbol (N+1) 3101-(N+1), and stream 1-2 datasymbol (N+2) 3101-(N+2)” in FIG. 35 have been described as “streams”above, they may be symbols including data symbols addressed to a certainterminal, symbols including control information symbols, or symbolsincluding multicast data symbols as described in other parts of thepresent specification.

Embodiment 4

The present embodiment will be described in relation to specificexamples of the communication systems described in relation toEmbodiments 1 to 3.

A communication system in the present embodiment is configured with a(plurality of) base station(s) and a plurality of terminals, forexample. For example, the communication system in FIGS. 7, 12, 17, 19,20, 26, 29 , or the like that is configured with base station 700 andterminals 704-1 and 704-2, and the like will be considered.

FIG. 37 illustrates an example of the configuration of base station(700).

Data 3701 and control data 3702 are input to logical channel generator3703, and the logical channel generator outputs logical channel signal3704. Logical channel signal 3704 is composed, for example, of a“Broadcast Control Channel (BCCH),” “Paging Control Channel (PCCH),”“Common Control Channel (CCCH),” “Multicast Control Channel (MCCH),”and/or “Dedicated Control Channel (DCCH),” which are logical controlchannels, “Dedicated Traffic Channel (DTCH)” and/or “Multicast TrafficChannel (MTCH),” which are logical data channels, and/or the like.

The “BCCH” is a downlink channel for broadcasting system controlinformation. The “PCCH” is a downlink paging information channel. The“CCCH” is a common control channel used when there is no downlink RadioResource Control (RRC) connection. The “MCCH” is a downlink controlchannel for multicast channel scheduling for one-to-many MultimediaBroadcast Multicast Service (MBMS). The “DCCH” is a downlink dedicatedcontrol channel used for a terminal with RRC connection. The “DTCH” is adownlink dedicated traffic channel for single terminal UE (UserEquipment), which is dedicated to user data. The “MTCH” is a downlinkone-to-many MBMS user-data channel.

Logical channel signal 3704 is input to transport channel generator3705, and the transport channel generator generates and outputstransport channel signal 3706. Transport channel signal 3706 iscomposed, for example, of a Broadcast Channel (BCH), Downlink SharedChannel (DL-SCH), Paging Channel (PCH), Multicast Channel (MCH), and/orthe like.

The “BCH” is a channel for system information broadcast over an entirecell. The “DL-SCH” is a channel for user data, control information, andsystem information. The “PCH” is a channel for paging informationbroadcast over the entire cell. The “MCH” is a channel for an MBMStraffic broadcast over the entire cell and for control.

Transport channel signal 3706 is input to physical channel generator3707, and the physical channel generator generates and outputs physicalchannel signal 3708. Physical channel signal 3708 is composed, forexample, of a Physical Broadcast Channel (PBCH), Physical MulticastChannel (PMCH), Physical Downlink Shared Channel (PDSCH), PhysicalDownlink Control Channel (PDCCH), and/or the like.

The “PBCH” is for transmission of a BCH transport channel. The “PMCH” isfor transmission of a MCH transport channel. The “PDSCH” is fortransmission of a DL-SCH and transport channel. The “PDCCH” is fortransmission of a downlink L1 (Layer 1)/L2 (Layer 2) control signal.

Physical channel signal 3708 is input to modulation signal generator3709, and the modulation signal generator generates and outputsmodulation signal 3710 based on physical channel signal 3708. Then, basestation 700 transmits modulation signal 3710 as a radio wave.

To begin with, a case where the base station performs unicastcommunication, i.e., specific communication, with a plurality ofterminals is considered.

In this case, for example, symbol group #1 of stream 1 (901-1), symbolgroup #2 of stream 1 (901-2), and symbol group #3 of stream 1 (901-3) inFIG. 9 may be control information broadcast to a plurality of terminalsin order for the base station to perform data communication with theplurality of terminals. That is, these symbol groups may be broadcastchannel information. The control information is, for example,information that can be used to realize data communication between thebase station and the terminals.

Here, a description will be given of the broadcast channel. The “PBCH,”“PMCH,” and “part of PD-SCH” of the physical channels (physical channelsignal 3708) correspond to the broadcast channel.

In addition, the “BCH,” “part of DL-SCH,” “PCH,” and “MCH” of thetransport channels (transport channel signal 3706) correspond to thebroadcast channel.

In addition, the “BCCH,” “CCCH,” “MCCH,” “part of DTCH,” and “MTCH” ofthe logical channels (logical channel signal 3704) correspond to thebroadcast channel.

For example, symbol group #1 of stream 2 (902-1), symbol group #2 ofstream 2 (902-2), and symbol group #3 of stream 2 (902-3) in FIG. 9 maybe control information broadcast by the base station to a plurality ofterminals in order for the base station to perform data communicationwith the plurality of terminals. That is, these symbol groups may bebroadcast channel information. The control information is, for example,information that can be used to realize data communication between thebase station and the terminals.

Note that, the “PBCH,” “PMCH,” and “part of PD-SCH” of the physicalchannels (physical channel signal 3708) correspond to the broadcastchannel.

Note also that, the “BCH,” “part of DL-SCH,” “PCH,” and “MCH” of thetransport channels (transport channel signal 3706) correspond to thebroadcast channel.

Note also that, the “BCCH,” “CCCH,” “MCCH,” “part of DTCH,” and “MTCH”of the logical channels (logical channel signal 3704) correspond to thebroadcast channel.

In this case, symbol group #1 of stream 1 (901-1), symbol group #2 ofstream 1 (901-2), and symbol group #3 of stream 1 (901-3) in FIG. 9 areas described in relation to the previous embodiments and, therefore, thedescriptions thereof are omitted. Further symbol group #1 of stream 2(902-1), symbol group #2 of stream 2 (902-2) and symbol group #3 ofstream 2 (902-3) in FIG. 9 are as described in relation to the previousembodiments and, therefore, the descriptions thereof are omitted.

Note that there may be a case where streams 2 such as symbol group #1 ofstream 2 (902-1), symbol group #2 of stream 2 (902-2), and/or symbolgroup #3 of stream 2 (902-3) in FIG. 9 are not transmitted. For example,when the base station transmits a signal of the broadcast channel, thebase station does not have to transmit the symbol groups of stream 2. Inthis case, streams 703-1, 703-2, and 703-3 are not transmitted from basestation 701 in the example of FIG. 7 .

For example, symbol group #1 of modulation signal 1 (1401-1), symbolgroup #2 of modulation signal 1 (1401-2), and symbol group #3 ofmodulation signal 1 (1401-3) in FIG. 14 may be control informationbroadcast by the base station to a plurality of terminals in order forthe base station to perform data communication with the plurality ofterminals. That is, these symbol groups may be broadcast channelinformation. The control information is, for example, information thatcan be used to realize data communication between the base station andthe terminals.

Note that, the “PBCH,” “PMCH,” and “part of PD-SCH” of the physicalchannels (physical channel signal 3708) correspond to the broadcastchannel.

Note also that, the “BCH,” “part of DL-SCH,” “PCH,” and “MCH” of thetransport channels (transport channel signal 3706) correspond to thebroadcast channel.

Note also that, the “BCCH,” “CCCH,” “MCCH,” “part of DTCH,” and “MTCH”of the logical channels (logical channel signal 3704) correspond to thebroadcast channel.

For example, symbol group #1 of modulation signal 2 (1402-1), symbolgroup #2 of modulation signal 2 (1402-2), and symbol group #3 ofmodulation signal 2 (1402-3) in FIG. 14 may be control informationbroadcast by the base station to a plurality of terminals in order forthe base station to perform data communication with the plurality ofterminals. That is, these symbol groups may be broadcast channelinformation. Note that, the control information is information that canbe used, for example, to realize data communication between the basestation and the terminal.

Note that, the “PBCH,” “PMCH,” and “part of PD-SCH” of the physicalchannels (physical channel signal 3708) correspond to the broadcastchannel.

Note also that, the “BCH,” “part of DL-SCH,” “PCH,” and “MCH” of thetransport channels (transport channel signal 3706) correspond to thebroadcast channel.

Note also that, the “BCCH,” “CCCH,” “MCCH,” “part of DTCH,” and “MTCH”of the logical channels (logical channel signal 3704) correspond to thebroadcast channel.

Note that, symbol group #1 of modulation signal 1 (1401-1), symbol group#2 of modulation signal 1 (1401-2), and symbol group #3 of modulationsignal 1 (1401-3) in FIG. 14 are as described in relation to theprevious embodiments and, therefore, the descriptions thereof areomitted. Symbol group #1 of modulation signal 2 (1402-1), symbol group#2 of modulation signal 2 (1402-2), and symbol group #3 of modulationsignal 2 (1402-3) in FIG. 14 are as described in relation to theprevious embodiments and, therefore, the descriptions thereof areomitted.

For example, stream 1-1 data symbol (1) (2501-1-1), stream 1-1 datasymbol (2) (2501-1-2), and stream 1-1 data symbol (3) (2501-1-3) in FIG.25 may be control information broadcast by the base station to aplurality of terminals in order for the base station to perform datacommunication with the plurality of terminals. That is, these symbolsmay be broadcast channel information. The control information is, forexample, information that can be used to realize data communicationbetween the base station and the terminals.

Note that, the “PBCH,” “PMCH,” and “part of PD-SCH” of the physicalchannels (physical channel signal 3708) correspond to the broadcastchannel.

Note also that, the “BCH,” “part of DL-SCH,” “PCH,” and “MCH” of thetransport channels (transport channel signal 3706) correspond to thebroadcast channel.

Note also that, the “BCCH,” “CCCH,” “MCCH,” “part of DTCH,” and “MTCH”of the logical channels (logical channel signal 3704) correspond to thebroadcast channel.

Note that, stream 1-1 data symbol (1) (2501-1-1), stream 1-1 data symbol(2) (2501-1-2), and stream 1-1 data symbol (3) (2501-1-3) in FIG. 25 areas described in relation to the previous embodiments and, therefore, thedescriptions thereof are omitted.

For example, stream 1-1 data symbol (M) (2501-1-M), stream 1-1 datasymbol (M+1) (2501-1-(M+1)), stream 1-1 data symbol (M+2)(2501-1-(M+2)), stream 1-2 data symbol (1) (3101-1), stream 1-2 datasymbol (2) (3101-2), and stream 1-2 data symbol (3) (3101-3) in FIGS. 31and 32 may be control information broadcast by the base station to aplurality of terminals in order for the base station to perform datacommunication with the plurality of terminals. That is, these symbolsmay be broadcast channel information. The control information is, forexample, information that can be used to realize data communicationbetween the base station and the terminals.

Note that, the “PBCH,” “PMCH,” and “part of PD-SCH” of the physicalchannels (physical channel signal 3708) correspond to the broadcastchannel.

Note also that, the “BCH,” “part of DL-SCH,” “PCH,” and “MCH” of thetransport channels (transport channel signal 3706) correspond to thebroadcast channel.

Note also that, the “BCCH,” “CCCH,” “MCCH,” “part of DTCH,” and “MTCH”of the logical channels (logical channel signal 3704) correspond to thebroadcast channel.

Note that stream 1-1 data symbol (M) (2501-1-M), stream 1-1 data symbol(M+1) (2501-1-(M+1)), stream 1-1 data symbol (M+2) (2501-1-(M+2)),stream 1-2 data symbol (1) (3101-1), stream 1-2 data symbol (2)(3101-2), and stream 1-2 data symbol (3) (3101-3) in FIGS. 31 and 32 areas described in relation to the previous embodiments and, therefore, thedescriptions thereof are omitted.

For example, stream 1-1 data symbol (M) (2501-1-M), stream 1-1 datasymbol (M+1) (2501-1-(M+1)), stream 1-1 data symbol (M+2)(2501-1-(M+2)), stream 1-2 data symbol (N) (3101-N), stream 1-2 datasymbol (N+1) (3101-(N+1)), and stream 1-2 data symbol (N+2) (3101-(N+2))in FIG. 35 may be control information broadcast by the base station to aplurality of terminals in order for the base station to perform datacommunication with the plurality of terminals. That is, these symbolsmay be broadcast channel information. The control information is, forexample, information that can be used to realize data communicationbetween the base station and the terminals.

Note that, the “PBCH,” “PMCH,” and “part of PD-SCH” of the physicalchannels (physical channel signal 3708) correspond to the broadcastchannel.

Note also that, the “BCH,” “part of DL-SCH,” “PCH,” and “MCH” of thetransport channels (transport channel signal 3706) correspond to thebroadcast channel.

Note also that, the “BCCH,” “CCCH,” “MCCH,” “part of DTCH,” and “MTCH”of the logical channels (logical channel signal 3704) correspond to thebroadcast channel.

For example, stream 2-1 data symbol (1) (3501-1), stream 2-1 data symbol(2) (3501-2), and stream 2-1 data symbol (3) (3501-3) in FIG. 35 may becontrol information broadcast by the base station to a plurality ofterminals in order for the base station to perform data communicationwith the plurality of terminals. That is, these symbols may be broadcastchannel information. The control information is, for example,information that can be used to realize data communication between thebase station and the terminals.

Note that, the “PBCH,” “PMCH,” and “part of PD-SCH” of the physicalchannels (physical channel signal 3708) correspond to the broadcastchannel.

Note also that, the “BCH,” “part of DL-SCH,” “PCH,” and “MCH” of thetransport channels (transport channel signal 3706) correspond to thebroadcast channel.

Note also that, the “BCCH,” “CCCH,” “MCCH,” “part of DTCH,” and “MTCH”of the logical channels (logical channel signal 3704) correspond to thebroadcast channel.

Note that stream 1-1 data symbol (M) (2501-1-M), stream 1-1 data symbol(M+1) (2501-1-(M+1)), stream 1-1 data symbol (M+2) (2501-1-(M+2)),stream 1-2 data symbol (N) (3101-N), stream 1-2 data symbol (N+1)(3101-(N+1)), and stream 1-2 data symbol (N+2) (3101-(N+2)) in FIG. 35are as described in relation to the previous embodiments and, therefore,the descriptions thereof are omitted. Stream 2-1 data symbol (1)(3501-1), stream 2-1 data symbol (2) (3501-2), and stream 2-1 datasymbol (3) (3501-3) in FIG. 35 are as described in relation to theprevious embodiments and, therefore, the descriptions thereof areomitted.

In FIGS. 9, 14, 25, 31, 32, and 35 , a single-carrier transmissionmethod or a multi-carrier transmission scheme such as OFDM may be usedfor transmission of data symbols. In addition, the temporal positions ofthe data symbols are not limited to those illustrated in FIGS. 9, 14,25, 31, 32, and 35 .

In addition, although the descriptions with reference to FIGS. 25, 31,32, and 35 have been given in which the horizontal axis represents thetime direction, the same implementation is possible even when thehorizontal axis represents a frequency (carrier) direction. Note that,when the horizontal axis represents the frequency (carrier) direction,the base station transmits each of the data symbols using one or morecarriers or subcarriers.

Note that, the symbol groups of stream 1 in FIG. 9 may contain data(unicast data) (or symbols) to be transmitted to a specific terminal.Similarly, the symbol groups of stream 2 in FIG. 9 may contain data(unicast data) (or symbols) to be transmitted to a specific terminal.

The symbol groups of stream 1 in FIG. 14 may contain data (unicast data)(or symbols) to be transmitted to a specific terminal. Similarly, thesymbol groups of stream 2 in FIG. 14 may contain data (unicast data) (orsymbols) to be transmitted to a specific terminal.

The symbols of stream 1-1 in FIG. 25 may contain data (unicast data) (orsymbols) to be transmitted to a specific terminal. The symbols of stream1-1 and stream 1-2 in FIGS. 31 and 32 may contain data (unicast data)(or symbols) to be transmitted to a specific terminal.

The PBCH may, for example, be configured “to be used to transmit minimuminformation (system bandwidth, system frame number, number oftransmission antennas, and the like) that a UE reads first after thecell search.”

The PMCH may, for example, be configured “to be used for operation ofMulticast-broadcast single-frequency network (MBSFN).”

The PDSCH may, for example, be configured “as a shared data channel fortransmitting downlink user data, and such that all data regardless ofwhether the data is C (Control)-plane/U (User)-plane data) is aggregatedand transmitted.”

The PDCCH may, for example, be configured “to be used to indicateallocation of radio resources to a user selected by scheduling by aneNodeB (gNodeB) (base station).

According to the embodiment described above, the base station transmitsdata symbols and control information symbols using a plurality oftransmission beams in multicast or broadcast data transmission. Inaddition, the terminals selectively receive a high-quality beam out of aplurality of transmission beams to receive the data symbols based on thereceived beam. Thus, as an effect of the present embodiment, theterminal can obtain high data reception quality.

Embodiment 5

In the present embodiment, a supplementary description will be given ofthe configurations of the symbol groups of stream 1 and stream 2 in FIG.9 transmitted by base station (700).

FIG. 38 illustrates an example of a frame configuration of stream 1transmitted by base station (700). In FIG. 38 , the horizontal axisrepresents the time direction, and the vertical axis represents thefrequency direction. FIG. 38 illustrates the frame configuration ofcarriers 1 to 40 at time 1 to time 10. That is, FIG. 38 is the frameconfiguration of a multi-carrier transmission system such as anOrthogonal Frequency Division Multiplexing (OFDM) system.

In FIG. 38 , symbol region 3801_1 of stream 1 extends from carrier 1 tocarrier 9 at time 1 to time 10.

Symbol group #i of stream 1 (3800_i) exists at carriers 10 to 20 at time1 to time 10. Note that, symbol group #i of stream 1 (3800_i)corresponds to symbol group #i of stream 1 (901-i) in FIG. 9 .

Symbol region 3801_2 of stream 1 extends from carrier 21 to carrier 40at time 1 to time 10.

In this case, the base station can use symbol regions 3801_1 and 3801_2of stream 1 in FIG. 38 when transmitting (unicasting) specific data toone or more terminals as described, for example, in Embodiment 4 or thelike.

Further, the base station can use symbol group #i of stream 1 (3800-i)in FIG. 38 to transmit multicast data as described in relation toEmbodiments 1, 4, and the like.

FIG. 39 illustrates an example of a frame configuration of stream 2transmitted by base station 700. In FIG. 39 , the horizontal axisrepresents the time direction, and the vertical axis represents thefrequency direction. FIG. 39 illustrates the frame configuration ofcarriers 1 to 40 at time 1 to time 10. That is, FIG. 39 illustrates theframe configuration of a multi-carrier transmission system such as anOFDM system.

In FIG. 39 , symbol region 3901_1 of stream 2 extends from carrier 1 tocarrier 9 at time 1 to time 10.

Symbol group #i (3900_i) of stream 2 exists at carriers 10 to 20 at time1 to time 10. Note that, symbol group #i (3900_i) of stream 2corresponds to symbol group #i (902-i) of stream 2 in FIG. 9 .

Symbol region 3901_2 of stream 2 extends from carrier 21 to carrier 40at time 1 to time 10.

In this case, the base station can use symbol regions 3901_1 and 3901_2of stream 2 in FIG. 39 when transmitting (unicasting) specific data toone or more terminals as described, for example, in Embodiment 4 or thelike.

Further, the base station can use symbol group #i of stream 2 (3900-i)in FIG. 39 to transmit multicast data as described in relation toEmbodiments 1, 4, and the like.

The base station transmits a symbol at carrier Y (Y is an integer offrom 1 through 40 in the case of FIG. 38 ) at time X (X is an integer offrom 1 through 10 in the case of FIG. 38 ) in FIG. 38 and a symbol atcarrier Y at time X in FIG. 39 using the same frequency and the sametime.

Symbol group #1 of stream 1 (901-1), symbol group #2 of stream 1(901-2), and symbol group #3 of stream 1 (901-3) illustrated in FIG. 9are as described in relation to the previous embodiments and, therefore,the descriptions thereof are omitted. That is, symbol groups #i ofstream 1 in FIG. 38 are the same as described for the previousembodiments in relation to the symbol groups of stream 1 in FIG. 9 and,therefore, the descriptions thereof are omitted.

Symbol group #1 of stream 2 (902-1), symbol group #2 of stream 2(902-2), and symbol group #3 of stream 3 (902-2) illustrated in FIG. 9are as described in relation to the previous embodiments and, therefore,the descriptions thereof are omitted. That is, symbol groups #i ofstream 2 in FIG. 39 are the same as described for the previousembodiments in relation to the symbol groups of stream 2 in FIG. 9 and,therefore, the descriptions thereof are omitted.

When there is any symbol existing at or after time 11 at any one ofcarriers 10 to 20 of the frame configuration illustrated in FIGS. 38 and39 , such a carrier may be used for multicast transmission or may beused for specific data transmission (unicast transmission).

When the base station transmits such a frame as illustrated in FIG. 9having the frame configuration illustrated in FIG. 38 or 39 , the basestation may perform the same operations as those in Embodiments 1 and 4.

According to the embodiment described above, the base station transmitsdata symbols and control information symbols using a plurality oftransmission beams in multicast or broadcast data transmission. Theterminals selectively receive a high-quality beam out of a plurality oftransmission beams to receive the data symbols based on the receivedbeam. Thus, as an effect of the present embodiment, the terminal canobtain high data reception quality.

Embodiment 6

In the present embodiment, a supplementary description will be given ofthe configurations of the symbol groups of modulation signal 1 andmodulation signal 2 in FIG. 14 transmitted by base station (700).

FIG. 40 illustrates an example of a frame configuration of modulationsignal 1 transmitted by base station 700. In FIG. 40 , the horizontalaxis represents the time direction, and the vertical axis represents thefrequency direction. FIG. 40 illustrates the frame configuration ofcarriers 1 to 40 at time 1 to time 10. That is, FIG. 40 illustrates theframe configuration of a multi-carrier transmission system such as anOrthogonal Frequency Division Multiplexing (OFDM) system.

In FIG. 40 , symbol region 4001_1 of modulation signal 1 extends fromcarrier 1 to carrier 9 at time 1 to time 10.

Symbol group #i of modulation signal 1 (4000-i) exists at carriers 10 to20 at time 1 to time 10. Symbol group #i of modulation signal 1 (4000-i)corresponds to symbol group #i of modulation signal 1 (1401-i) in FIG.14 .

Symbol region 4001_2 of modulation signal 1 extends from carrier 21 tocarrier 40 at time 1 to time 10.

In this case, the base station can use symbol regions 4001_1 and 4001_2of modulation signal 1 in FIG. 40 when transmitting (unicasting)specific data to one or more terminals as described, for example, inEmbodiment 4 or the like.

Further, the base station can use symbol group #i of modulation signal 1(4000-i) in FIG. 40 to transmit multicast data as described in relationto Embodiments 1, 4, and the like.

FIG. 41 illustrates an example of a frame configuration of modulationsignal 2 transmitted by base station (700). In FIG. 41 , the horizontalaxis represents the time direction and the vertical axis represents thefrequency direction. FIG. 41 illustrates the frame configuration ofcarriers 1 to 40 at time 1 to time 10. That is, FIG. 41 illustrates theframe configuration of a multi-carrier transmission system such as theOFDM system.

In FIG. 41 , symbol region 4101_1 of modulation signal 2 extends fromcarrier 1 to carrier 9 at time 1 to time 10.

Symbol group #i (4100-i) of modulation signal 2 exists at carriers 10 to20 at time 1 to time 10. Symbol group #i (4100-i) of modulation signal 2corresponds to symbol group #i (1402-i) of modulation signal 2 in FIG.14 .

Symbol region 4101_2 of modulation signal 2 extends from carrier 21 tocarrier 40 at time 1 to time 10.

In this case, the base station can use symbol regions 4101_1 and 4101_2of modulation signal 2 in FIG. 41 when transmitting (unicasting)specific data to one or more terminals as described, for example, inEmbodiment 4 or the like.

Further, the base station can use symbol group #i of modulation signal 2(4100-i) in FIG. 41 to transmit multicast data as described in relationto Embodiments 1, 4, and the like.

The base station transmits a symbol at carrier Y (Y is an integer offrom 1 through 40 in the case of FIG. 40 ) at time X (X is an integer offrom 1 through 10 in the case of FIG. 40 ) in FIG. 40 and a symbol atcarrier Y at time X in FIG. 41 using the same frequency and the sametime.

Symbol group #1 of modulation signal 1 (1401-1), symbol group #2 ofmodulation signal 1 (1401-2), and symbol group #3 of modulation signal 1(1401-3) illustrated in FIG. 14 are as described in relation to theprevious embodiments and, therefore, the descriptions thereof areomitted. That is, symbol groups #i of modulation signal 1 in FIG. 40 arethe same as described for the previous embodiments in relation to thesymbol groups of modulation signal 1 in FIG. 14 and, therefore, thedescriptions thereof are omitted.

Symbol group #1 of modulation signal 2 (1402-1), symbol group #2 ofmodulation signal 2 (1402-2), and symbol group #3 of modulation signal 2(1402-3) illustrated in FIG. 14 are as described in relation to theprevious embodiments and, therefore, the descriptions thereof areomitted. That is, symbol groups #i of modulation signal 2 in FIG. 41 arethe same as described for the previous embodiments in relation to thesymbol groups of modulation signal 2 in FIG. 14 and, therefore, thedescriptions thereof are omitted.

When there is any symbol existing at or after time 11 at any one ofcarriers 10 to 20 of the frame configuration illustrated in FIGS. 40 and41 , such a carrier may be used for multicast transmission or may beused for specific data transmission (unicast transmission).

When the base station transmits such a frame as illustrated in FIG. 14having the frame configuration illustrated in FIG. 40 or 41 , the basestation may perform the same operations as those in Embodiments 1 and 4.

A description will be given of an example of a method of using symbolregions 3801_1 and 3801_2 of stream 1 in FIG. 38 , symbol regions 3901_1and 3901_2 of stream 2 in FIG. 39 , symbol regions 4001_1 and 4001_2 ofmodulation signal 1 in FIG. 40 , and symbol regions 4101_1 and 4102_2 ofmodulation signal 2 in FIG. 41 in the above description.

FIG. 42 illustrates an example of allocation of “symbol regions 3801_1and 3801_2 of stream 1 in FIG. 38 , symbol regions 3901_1 and 3901_2 ofstream 2 in FIG. 39 , symbol regions 4001_1 and 4001_2 of modulationsignal 1 in FIG. 40 , and symbol regions 4101_1 and 4102_2 of modulationsignal 2 in FIG. 41 to terminals. Note that, the horizontal axisrepresents the time direction and the vertical axis represents thefrequency (carrier) direction in FIG. 42 .

As illustrated in FIG. 42 , “symbol regions 3801_1 and 3801_2 of stream1 in FIG. 38 , symbol regions 3901_1 and 3901_2 of stream 2 in FIG. 39 ,symbol regions 4001_1 and 4001_2 of modulation signal 1 in FIG. 40 , andsymbol regions 4101_1 and 4102_2 of modulation signal 2 in FIG. 41 ” arefrequency-divided and allocated to the terminals, for example. FIG. 42illustrates symbol group 4201_1 allocated to terminal #1, symbol group4201_2 allocated to terminal #2, and symbol group 4201_3 allocated toterminal #3.

For example, base station 700 communicates with terminal #1, terminal#2, and/or terminal #3. When transmitting data to terminal #1, the basestation transmits the data to terminal #1 using “symbol group 4201_1allocated to terminal #1” in FIG. 42 . When transmitting data toterminal #2, the base station transmits the data to terminal #2 using“symbol group 4201_2 allocated to terminal #2” in FIG. 42 . Whentransmitting data to terminal #3, the base station transmits the data toterminal #3 using “symbol group 4201_3 allocated to terminal #3” in FIG.42 .

Note that the allocation method for allocation to the terminals is notlimited to that illustrated in FIG. 42 . For example, the frequency band(the number of carriers) may vary with time, or may be set in anymanner. The allocation method for allocation to the terminals may alsobe changed with time.

FIG. 43 illustrates an example different from FIG. 42 in which “symbolregions 3801_1 and 3801_2 of stream 1 in FIG. 38 , symbol regions 3901_1and 3901_2 of stream 2 in FIG. 39 , symbol regions 4001_1 and 4001_2 ofmodulation signal 1 in FIG. 40 , and symbol regions 4101_1 and 4102_2 ofmodulation signal 2 in FIG. 41 are allocated to terminals. Note that,the horizontal axis represents the time direction and the vertical axisrepresents the frequency (carrier) direction in FIG. 43 .

As illustrated in FIG. 43 , “symbol regions 3801_1 and 3801_2 of stream1 in FIG. 38 , symbol regions 3901_1 and 3901_2 of stream 2 in FIG. 39 ,symbol regions 4001_1 and 4001_2 of modulation signal 1 in FIG. 40 , andsymbol regions 4101_1 and 4102_2 of modulation signal 2 in FIG. 41 ” aretime-divided and frequency-divided, and allocated to the terminals, forexample. FIG. 43 illustrates symbol group (4301_1) allocated to terminal#1, symbol group (4301_2) allocated to terminal #2, symbol group(4301_3) allocated to terminal #3, symbol group (4301_4) allocated toterminal #4, symbol group (4301_5) allocated to terminal #5, and symbolgroup (4301_6) allocated to terminal #6.

For example, base station (700) communicates with terminal #1, terminal#2, terminal #3, terminal #4, terminal #5, and terminal #6. Whentransmitting data to terminal #1, the base station transmits the datausing “symbol group 4301_1 allocated to terminal #1” in FIG. 43 . Whentransmitting data to terminal #2, the base station transmits the data toterminal #2 using “symbol group 4301_2 allocated to terminal #2” in FIG.43 . When transmitting data to terminal #3, the base station transmitsthe data to terminal #3 using “symbol group 4301_3 allocated to terminal#3” in FIG. 43 . When transmitting data to terminal #4, the base stationtransmits the data to terminal #4 using “symbol group 4301_4 allocatedto terminal #4” in FIG. 43 . When transmitting data to terminal #5, thebase station transmits the data to terminal #5 using “symbol group4301_5 allocated to terminal #5” in FIG. 43 . When transmitting data toterminal #6, the base station transmits the data using “symbol group4301_6 allocated to terminal #6” in FIG. 43 .

Note that the allocation method for allocation to the terminals is notlimited to that illustrated in FIG. 43 . For example, the frequency band(number of carriers) and the time width may be changed or may be set inany manner. The allocation method for allocation to the terminals mayalso be changed with time.

Further, weighted combination different for each carrier may beperformed on the symbol regions of stream 1, the symbol regions ofstream 2, the symbol regions of modulation signal 1, and the symbolregions of modulation signal 2 in FIGS. 38, 39, 40, and 41 , or a methodfor the weighted combination may be determined on the basis of aplurality of carriers. Further, a weighted combination parameter may beset for each of the terminals to which the symbol regions are allocatedas illustrated in FIGS. 42 and 43 . Setting the method for the weightedcombination for the carriers is not limited to these examples.

According to the embodiment described above, the base station transmitsdata symbols and control information symbols using a plurality oftransmission beams in multicast or broadcast data transmission. Theterminals selectively receive a high-quality beam out of a plurality oftransmission beams to receive the data symbols based on the receivedbeam. Thus, as an effect of the present embodiment, the terminal canobtain high data reception quality.

Embodiment 7

Base station 700 in FIGS. 7, 12, 17, 18, 19, 20, and 22 , or the basestation described in relation to other embodiments in the presentspecification may be configured as illustrated in FIG. 44 .

The operation of the base station of FIG. 44 will be described below.Components in FIG. 44 that operate in the same manner as those in FIG. 1or 3 are provided with the same reference numerals, and the descriptionsof those components are omitted.

Signals 103_1, 103_2, . . . , and 103_M after signal processing andcontrol signal 159 are input to weighting combiner 301, and theweighting combiner performs weighted combination based on control signal159 and outputs weighted-combination signals 4401_1, 4401_2, . . . , and4401_K. Note that M is an integer equal to or greater than 2 and K is aninteger equal to or greater than 2.

For example, when signal 103_i (i is an integer of from 1 through M)after the signal processing is represented by ui(t) (t denotes time) andsignal 4401_g (g is an integer of from 1 through K) resulting from theweighted combination is represented by vg(t), vg(t) can be expressed bythe following equation.

$\begin{matrix}\lbrack 7\rbrack &  \\\begin{matrix}{{v_{g}(t)} = {{Q_{g1} \times {u_{1}(t)}} + {Q_{g2} \times {u_{2}(t)}} + \ldots + {Q_{gM} \times {u_{M}(t)}}}} \\{= {\sum\limits_{j = 1}^{M}{Q_{gj} \times {u_{j}(t)}}}}\end{matrix} & \left( {{Equation}7} \right)\end{matrix}$

Signal 4401-g resulting from the weighted combination and control signal159 are input to radio 104-g, and the radio performs predeterminedprocessing based on control signal 159 to generate and outputtransmission signal 105-g. Transmission signal 105-g is then transmittedfrom antenna 303_1.

The transmission method supported by the base station may be amulticarrier system such as OFDM or a single carrier system. Inaddition, the base station may support both the multicarrier system andthe single carrier system. In this case, the present embodiment can beimplemented by employing any one of a plurality of methods forgenerating a modulation signal of a single carrier system. Examples ofthe single carrier system include “Discrete Fourier Transform(DFT)-Spread Orthogonal Frequency Division Multiplexing (OFDM),”“Trajectory Constrained DFT-Spread OFDM,” “OFDM based Single Carrier(SC),” “Single Carrier (SC)-Frequency Division Multiple Access (FDMA),”“Guard interval DFT-Spread OFDM,” and the like, for example.

While Equation 7 is described as a function of time, the equation mayalso be a function of time and frequency in the case of a multi-carriersystem such as the OFDM system.

For example, in the OFDM system, the weighted combination different foreach carrier may be performed, or a method for the weighted combinationmay be determined on the basis of a plurality of carriers. Setting themethod for the weighted combination for the carriers is not limited tothese examples.

(Supplement 6)

It is needless to say that the embodiments described in the presentspecification may be implemented by combining a plurality ofmiscellaneous contents such as the supplements.

The configuration of the base station is not limited to the examples ofFIGS. 1 and 3 . The present disclosure can be implemented by any basestation as long as the base station includes a plurality of transmissionantennas and generates and transmits a plurality of transmission beams(transmission directional beams).

In addition, the embodiments are merely examples. For example, eventhough examples of “modulation scheme, error correction coding scheme(error correction code, code length, coding rate, and the like for use),control information, and the like” are given, another “modulationscheme, error correction coding scheme (error correction code, codelength, coding rate, and the like for use), control information, and thelike” can be applied to implement the present disclosure with the sameconfiguration.

The embodiments and miscellaneous contents described in the presentspecification can also be implemented using a modulation scheme otherthan the modulation scheme described in the present specification. Forexample, APSK (e.g., 16APSK, 64APSK, 128APSK, 256APSK, 1024APSK,4096APSK, or the like), PAM (e.g., 4PAM, 8PAM, 16PAM, 64PAM, 128PAM,256PAM, 1024PAM, 4096PAM, or the like), PSK (e.g., BPSK, QPSK, 8PSK,16PSK, 64PSK, 128PSK, 256PSK, 1024PSK, 4096PSK, or the like), QAM (e.g.,4QAM, 8QAM, 16QAM, 64QAM, 128QAM, 256QAM, 1024QAM, 4096QAM, or thelike), and/or the like may be applied, and uniform mapping andnon-uniform mapping may be used in each of the modulation schemes. Inaddition, the method of arranging signal points (e.g., 2, 4, 8, 16, 64,128, 256, or 1024 signal points) on the I-Q plane (modulation schemewith 2, 4, 8, 16, 64, 128, 256, or 1024 signal points or other number ofsignal points) is not limited to the signal-point arrangement method ofthe modulation scheme indicated in the present specification.

In the present specification, it is considered that acommunication/broadcasting device such as a broadcasting station, a basestation, an access point, a terminal, a mobile phone, or the like isprovided with the transmission apparatus, for example. In this case, itis considered that a communication device such as a television, a radio,a terminal, a personal computer, a mobile phone, an access point, a basestation, or the like is provided with the reception apparatus. Further,it is considered that the transmission apparatus and the receptionapparatus in the present disclosure are devices having a communicationfunction, and the devices are configured to be capable of beingconnected via some interface to an apparatus for executing anapplication of a television, a radio, a personal computer, a mobilephone, or the like. In addition, symbols other than data symbols, forexample, a pilot symbol (preamble, unique word, postamble, referencesymbol, and the like) and a control information symbol may be arrangedin any manner in a frame in the present embodiment. Those symbols called“pilot symbol” and “control information symbol” in the presentembodiment may also be called by any names. That is, those symbols, evenwith different names, have the same function.

The pilot symbol may be a known symbol modulated using PSK modulation ina transceiver, for example. A receiver performs frequencysynchronization, time synchronization, channel estimation of eachmodulation signal (estimation of Channel State Information (CSI)),signal detection, and/or the like using this symbol. Alternatively, thereceiver may be able to know a symbol transmitted by a transmitter bysynchronizing the pilot symbol.

In addition, the control information symbol is a symbol for transmittinginformation other than data (data of an application or the like) that isto be transmitted to a communication partner for realizingcommunication. For example, the control information symbol transfers amodulation scheme, an error correction coding scheme, an errorcorrection coding scheme, a coding rate of the error correction codingscheme, configuration information of a higher layer, and/or the likeused for communication.

Note that the present disclosure is not limited to each of theembodiments, and can be implemented with various modifications. Forexample, although the embodiments have been described as operations ofthe communication apparatus, the present disclosure is not limited tothe embodiments, and can also be described as an operation of softwarefor implementing a communication method.

For example, a program for executing the above communication method maybe stored in a ROM in advance, and the program may be operated by a CPU.

Further, the program for executing the above communication method may bestored in a computer-readable storage medium, the program stored in thestorage medium may be recorded in a RAM of the computer, and thecomputer may be operated in accordance with the program.

The configurations of each of the above embodiments may typically beimplemented as an LSI that is an integrated circuit having an inputterminal and an output terminal. These configurations may beindividually formed into single chips, or may be formed into one chip toinclude all or some of the configurations of each of the embodiments. Inthis case, an appellation “LSI” is employed. However, depending on thedegree of integration, appellations such as IC, system LSI, super LSI,and ultra LSI may be employed. In addition, the technique of circuitintegration is not limited to the LSI, and it may be realized by adedicated circuit or a general-purpose processor. An FPGA that can beprogrammed after LSI fabrication or a reconfigurable processor that canreconfigure connections and settings of circuit cells inside the LSI maybe used. If future integrated circuit technology replaces LSIs as aresult of the advancement of semiconductor technology or otherderivative technology, the functional blocks could be integrated usingthe future integrated circuit technology. Biotechnology can also beapplied.

The various frame configurations have been described in the presentspecification. For example, a base station (AP) including thetransmission apparatus of FIG. 1 transmits the modulation signals of theframe configurations described herein using a multi-carrier scheme suchas the OFDM scheme. In this case, an application method can beconsidered in which, when a terminal (user) communicating with the basestation (AP) transmits a modulation signal, the modulation signaltransmitted by the terminal is of a single carrier system. The basestation (AP) can transmit a data symbol group to a plurality ofterminals at the same time by using the OFDM system, or also can reducepower consumption by using the single carrier system.

Further, a terminal may apply a Time Division Duplex (TDD) scheme fortransmitting a modulation scheme using a part of a frequency band usedfor a modulation signal transmitted by the base station (AP).

The configuration of each of antenna sections 106-1, 106-2, . . . , and106-M in FIG. 1 is not limited to the configuration described inrelation to the embodiment. For example, antenna sections 106-1, 106-2,. . . , and 106-M do not have to be configured with a plurality ofantennas. Further, signal 159 does not have to be input to antennasections 106-1, 106-2, . . . , and 106-M.

The configuration of each of antenna sections 401-1, 401-2, . . . , and401-N in FIG. 4 is not limited to the configuration described inrelation to the embodiment. For example, antenna sections 401-1, 401-2,. . . , and 401-N do not have to be configured with a plurality ofantennas. Further, signal 410 does not have to be input to antennasections 401-1, 401-2, . . . , and 401-N.

Note that, the transmission method supported by the base station and theterminals may be a multicarrier system such as OFDM or a single carriersystem. The base station may also support both the multicarrier andsingle carrier schemes. In this case, the present embodiment can beimplemented by employing any one of a plurality of methods forgenerating a modulation signal of a single carrier system. Examples ofthe single carrier system include “Discrete Fourier Transform(DFT)-Spread Orthogonal Frequency Division Multiplexing (OFDM),”“Trajectory Constrained DFT-Spread OFDM,” “OFDM based Single Carrier(SC),” “Single Carrier (SC)-Frequency Division Multiple Access (FDMA),”“Guard interval DFT-Spread OFDM,” and the like, for example.

Further, there is at least multicast (broadcast) data in information #1(101_1), information #2 (101_2), . . . , and information #M (101_M) inFIGS. 1, 3, and 44 . For example, when information #1 101_1 is multicastdata in FIG. 1 , a plurality of streams or modulation signals includingthis data are generated by signal processor 102 and output from theantenna.

When information #1 (101_1) is multicast data in FIG. 3 , a plurality ofstreams or modulation signals including this data are generated bysignal processor 102 and/or weighting combiner 301, and are output fromthe antenna.

When information #1 (101_1) is multicast data in FIG. 44 , a pluralityof streams or modulation signals including this data are generated bysignal processor 102 and/or weighting combiner 301, and are output fromthe antenna.

Note that, the state of the plurality of streams or modulation signalsis as described with reference to FIGS. 7, 9, 12, 14, 17, 18, and 19 .

Further, data addressed to a specific terminal may be included ininformation #1 (101_1), information #2 (101_2), . . . , or information#M (101_M) in FIGS. 1, 3, and 44 . This point is as described inrelation to the embodiments of the present specification.

Note that, at least one of a Field Programmable Gate Array (FPGA) and aCentral Processing Unit (CPU) may be configured to allow download of allor part of software through radio communication or wired communication,which is required for implementing the communication methods describedin the present disclosure. Further, at least one of the FPGA and the CPUmay be configured to allow download of all or part of software forupdate through radio communication or wired communication. In addition,digital signal processing described in the present disclosure may beexecuted by at least one of the FPGA and the CPU operated based ondownloaded software stored in a storage section.

At this time, the device including at least one of the FPGA and the CPUmay be connected to a communication modem by radio or by wire, and thecommunication methods described in the present disclosure may beimplemented by the device and the communication modem.

For example, the communication apparatus such as the base station, theAP, or the terminal described in the present specification may includeat least one of the FPGA and the CPU, and the communication apparatusmay include an interface for externally acquiring software for operatingat least one of the FPGA and the CPU. Further, the communicationapparatus may include a storage section for storing the externallyacquired software, and the signal processing described in the presentdisclosure may be realized by operating the FPGA or the CPU based on thestored software.

Embodiment 8

FIG. 45 illustrates an example of a configuration of a mesh network inwhich repeaters of a radio signal (hereinafter, simply referred to as“repeaters”) are used.

As illustrated in FIG. 45 , a plurality of repeaters are arranged at aplurality of points in a predetermined area, respectively, andconstitute a mesh type radio backhaul.

For example, repeater 4800B transmits to repeater 4800C a signalreceived from repeater 4800A. Repeater 4800B also transmits the signalreceived from repeater 4800A to edge node 4810 connected to repeater4800B. Repeater 4800B also transmits to another repeater 4800C a signalreceived from edge node 4810 connected to repeater 4800B.

For example, the edge node may be a gateway device for a gateway to ahome network. This is a use case called Wireless To The Home (WTTH). Theedge node may also be a gateway device for a gateway to a network in abuilding. This is a use case called Wireless to the building (WTTB). Theedge node may also be a Wi-Fi access point, for example. Thus, use casesin which the edge node is wirelessly connected is referred tocollectively as Wireless to the X (WTTX).

Note that the term “repeater” is merely an example, and the repeater mayalso be referred to as a communication apparatus, a base station, or anode, for example. Therefore, the implementation described as theoperation of the base station in the present specification may also bethe operation of the repeater in the present embodiment.

FIG. 46 schematically illustrates an example of connection betweenrepeaters according to Embodiment 8.

In FIG. 46 , repeater 4900B directs beam directivity toward repeater4900A for transmitting or receiving a modulation signal. That is,repeater 4900B performs beamforming BF1 toward repeater 4900A. Repeater4900B directs beam directivity toward repeater 4900C for transmitting orreceiving a modulation signal. That is, repeater 4900B performsbeamforming BF2 toward repeater 4900C.

In FIG. 46 , repeater 4900B receives modulation signal 4902A transmittedby repeater 4900A, and transmits modulation signal 4901C correspondingto modulation signal 4901A to repeater 4900C. In addition, repeater4900B receives modulation signal 4902C transmitted by repeater 4900C,and transmits modulation signal 4901A corresponding to modulation signal4902C to repeater 4900A. That is, repeater 4900B relays the modulationsignals between repeater 4900A and repeater 4900C.

Note that modulation signal 4902A and modulation signal 4901C are notnecessarily the same modulation signal. Modulation signal 4902A andmodulation signal 4901C at least contain the same information (which isreferred to as “first information”) or contain information relevant tothe first information. The modulation scheme for generating modulationsignal 4902A and the modulation scheme for generating modulation signal4901C are not necessarily the same.

Further, the error correction coding scheme for generating modulationsignal 4902A and the error correction coding scheme for generatingmodulation signal 4901C are not necessarily the same. In addition,modulation signal 4902C and modulation signal 4901A are not necessarilythe same modulation signal. Modulation signal 4902C and modulationsignal 4901A contain at least the same information (which is referred toas “second information”) or contain information relevant to the secondinformation.

Further, the modulation scheme for generating modulation signal 4902Cand the modulation scheme for generating modulation signal 4901A are notnecessarily the same. Furthermore, the error correction coding schemefor generating modulation signal 4902C and the error correction codingscheme for generating modulation signal 4901A are not necessarily thesame.

Repeater 4900B performs beamforming BF1 toward repeater 4900A whentransmitting modulation signal 4901A to repeater 4900A and whenreceiving modulation signal 4902A from repeater 4900A. Thus, thereception quality of the modulation signals between repeater 4900B andrepeater 4900A improves.

Repeater 4900B also performs beamforming BF2 toward repeater 4900C whentransmitting modulation signal 4901C to repeater 4900C and whenreceiving modulation signal 4902C from repeater 4900C. Thus, thereception quality of the modulation signals between repeater 4900B andrepeater 4900C improves.

FIG. 47 illustrates an example of slot allocation to repeater 4900B ofFIG. 46 .

A slot for transmission of a modulation signal (hereinafter referred toas a “transmission slot”) and a slot for reception of a modulationsignal (hereinafter referred to as a “reception slot”) are allocated torepeaters. Each one of the slots is a resource unit occupying apredetermined time period and frequency as illustrated in FIG. 47 , andis arranged on the time axis. Note that, the slot represented as oneslot in FIG. 47 (for example, transmission slot 5001A) may be formed bya plurality of slots. The same applies to other FIGS. 48, 50, 51, 53,54, 55, and 56 .

The example of FIG. 47 illustrates that transmission slot 5001A fortransmission to repeater 4900A, transmission slot 5001C for transmissionto repeater 4900C, reception slot 5002C for reception from repeater4900C, and reception slot 5002A for reception from repeater 4900C areallocated to repeater 4900B successively on the time axis. Note that, atransmission period and a reception period combined with each otherconstitute one TDD interval, which will be described later.

That is, FIG. 47 illustrates an example in which the transmission slotsare allocated consecutively on the time axis and the reception slots areallocated consecutively on the time axis. Note that, a period in whichtransmission slots are consecutively allocated is referred to as atransmission period, and a period in which reception slots areconsecutively allocated is referred to as a reception period.

Note that, there may also be another symbol (e.g., a control informationsymbol or a data symbol) between transmission slot 5001A andtransmission slot 5001C, or there may also be a time period during whichno modulation signal exists. In addition, there may also be anothersymbol (e.g., a control information symbol or a data symbol) betweenreception slot 5002C and reception slot 5002A, or there may also be atime period during which no modulation signal exists.

The period lengths of transmission slot 5001A and transmission slot5001C may be the same as each other or different from each other.Similarly, the period lengths of reception slot 5002C and reception slot5002A may be the same as each other or different from each other. Thesame applies to other FIGS. 48, 50, 51, 53, 54, 55, and 56 .

Note that, FIG. 47 illustrates the slot allocation to repeater 4900B ata certain time, and except for this time, the transmission slot and thereception slot may be allocated to repeater 4900B in the same order asin FIG. 47 , or the transmission slot and the reception slot may beallocated in a different order than in FIG. 47 . The same applies toother FIGS. 48, 50, 51, 53, 54, 55, and 56 .

Note that, data transmitted in transmission slots 5001A and 5001C inFIG. 47 is data received in a reception slot preceding by one or moreTDD intervals or in a frame preceding by one or more frames, and datareceived in reception slots 5002A and 5002C in FIG. 47 is data to betransmitted in a transmission slot succeeding by one or more TDDintervals or in a frame succeeding by one or more frames. The sameapplies to other FIGS. 48, 50, 51, 53, 54, 55, and 56 .

Repeater 4900B directs the beam directivity toward repeater 4900A (i.e.,performs directivity control) during the period of transmission slot5001A for transmitting the modulation signal. Repeater 4900B alsodirects the beam directivity toward repeater 4900C during the period oftransmission slot 5001C for transmitting the modulation signal.

Repeater 4900B also directs the beam directivity toward repeater 4900Cduring the period of reception slot 5002C for receiving the modulationsignal transmitted by repeater 4900C. Repeater 4900B also directs thedirectivity toward repeater 4900A during the period of reception slot5002A for receiving the modulation signal transmitted by repeater 4900A.

As illustrated in FIG. 47 , consecutive allocation of at least thetransmission slots or the reception slots (to a certain time and acertain frequency band) allows reduction in load on a power amplifier inrepeater 4900B, resulting in reduction in power consumption of repeater4900B. In addition, when a guard period is provided between transmissionslot 5001A and transmission slot 5001C, it is possible to shorten theguard period so as to improve the data transmission rate.

FIG. 48 illustrates a variation of slot allocation to repeater 4900B ofFIG. 46 .

An example of FIG. 48 illustrates that reception slot 5102C forreception from repeater 4900C, transmission slot 5101C for transmissionto repeater 4900C, reception slot 5102A for reception from repeater4900A, and transmission slot 5101A for transmission to repeater 4900Aare allocated to repeater 4900B successively on the time axis. That is,FIG. 48 illustrates an example of pairs of slots each of which iscomposed of the “reception slot and transmission slot for the samerepeater” allocated consecutively.

A guard period may be provided between reception slot 5102C andtransmission slot 5101C. Similarly, a guard period may be providedbetween reception slot 5102A and transmission slot 5101A. Note that, theguard period is a period in which no modulation signal exists, forexample.

Repeater 4900B directs the beam directivity toward repeater 4900C(performs directivity control) during the period of reception slot 5102Cfor receiving the modulation signal transmitted by repeater 4900C.Repeater 4900B directs the beam directivity toward repeater 4900C duringthe period of transmission slot 5101C for transmitting the modulationsignal.

Repeater 4900B directs the beam directivity toward repeater 4900A duringthe period of reception slot 5102A for receiving the modulation signaltransmitted by repeater 4900A. Repeater 4900B directs directivity towardrepeater 4900A during the period of transmission slot 5101A fortransmitting the modulation signal.

The reception slot and the transmission slot for the same repeater areconsecutively allocated as illustrated in FIG. 48 , so that repeater4900B only has to direct the beam directivity toward repeater 4900Cduring the period of reception slot 5102C and transmission slot 5101C,and only has to direct the beam directivity toward repeater 4900A duringthe period of reception slot 5102A and transmission slot 5101A.Therefore, the directivity control of the beam in repeater 4900B isfacilitated.

Note that the slot allocation system illustrated in FIG. 47 and the slotallocation system illustrated in FIG. 48 may be switched according toconditions of radio communication, propagation environment, and/or thelike. For example, repeater 4900B may transmit predetermined switchinginformation to repeaters 4900A and 4900C according to a change in suchconditions to switch the slot allocation system.

Accordingly, a suitable transmission method is selected according to acommunication condition, so that it is possible to obtain an effect ofachieving both the improvement of the reception data quality and theimprovement of the data transmission rate.

Embodiment 9

FIG. 49 illustrates an example of connection between repeaters accordingto Embodiment 9.

FIG. 49 differs from FIG. 46 in that device 5210 is connected torepeater 5200B.

Device 5210 is an image capturing device for capturing a moving image ora still image (e.g., a surveillance camera), a predetermined sensor, ora radio base station, for example. Repeater 5200B and device 5210 areconnected to each other by an interface (I/F) such as a USB. However,the I/F between repeater 5200B and device 5210 is not limited to this,and may be a gigabit class Ethernet, for example. The I/F is not limitedto a wired interface, but may also be a radio interface. Repeater 5200Band device 5210 may also constitute a single device or a single system.

As in FIG. 46 , repeater 5200B receives modulation signal 5202Atransmitted by repeater 5200A, and transmits modulation signal 5201Ccorresponding to received modulation signal 5202A to repeater 5200C.Repeater 5200B also receives modulation signal 5202C transmitted byrepeater 5200C, and transmits modulation signal 5201A corresponding toreceived modulation signal 5202C to repeater 5200A. That is, repeater5200B relays the modulation signal between repeater 5200A and repeater5200C.

Note that modulation signal 5202A and modulation signal 5201C are notnecessarily the same modulation signal. Modulation signal 5202A andmodulation signal 5201C at least contain the same information (which isreferred to as first information) or information relevant to the firstinformation.

Note also that, the modulation scheme for generating modulation signal5202A and the modulation scheme for generating modulation signal 5201Care not necessarily the same. Further, the error correction codingscheme for generating modulation signal 5202A and the error correctioncoding scheme for generating modulation signal 5201C are not necessarilythe same. In addition, modulation signal 5202C and modulation signal5201A are not necessarily the same modulation signal.

Modulation signal 5202C and modulation signal 5201A at least contain thesame information (which is referred to as second information) or containinformation relevant to the second information. In addition, themodulation scheme for generating modulation signal 5202C and themodulation scheme for generating modulation signal 5201A are notnecessarily the same. Further, the error correction coding scheme forgenerating modulation signal 5202C and the error correction codingscheme for generating modulation signal 5201A are not necessarily thesame.

In addition, repeater 5200B receives data transmitted by device 5210connected to repeater 5200B or a modulation signal including the data,generates a modulation signal including at least part of the datatransmitted by device 5210 or at least part of data relevant to thetransmitted data, and transmits the modulation signal to repeater 5200Aas modulation signal 5203A.

Repeater 5200B also receives data transmitted by device 5210 or amodulation signal including the data, generates a modulation signalincluding at least part of the data transmitted by device 5210 or atleast part of data relevant to the transmitted data, and transmits themodulation signal to repeater 5200C as modulation signal 5203C.

Note that, an example of the “relevant information” and “relevant data”described above will be described.

For example, apparatus A performs first encoding on a video of a firstscene to generate first data, and performs second encoding on the videoof the first scene to generate second data. At this time, the first dataand the second data are in a relationship of “relevant information” or“relevant data.”

Further, apparatus B obtains the generated first data, generates thevideo of the first scene from the first data, and performs the secondencoding again to generate the second data, for example. At this time,the first data and the second data are in a relationship of “relevantinformation” or “relevant data.” Note that, this point is applicable toall the embodiments included in the present specification.

Note that, the basic operation of the directivity control of the beamfor transmission and reception of the modulation signal is the same asin the case of FIG. 46 and, therefore, the description thereof isomitted.

FIG. 50 illustrates an example of slot allocation to repeater 5200B ofFIG. 49 . Note that, the horizontal axis represents time and thevertical axis represents the frequency in FIG. 50 . In addition, a firstchannel formed in a first frequency band and a second channel formed ina second frequency band are illustrated in FIG. 50 .

FIG. 50 illustrates that transmission slot 5301A for transmission torepeater 5200A, transmission slot 5301C for transmission to repeater5200C, reception slot 5302C for reception from repeater 5200C, andreception slot 5302A for reception from repeater 5200C are allocated torepeater 5200B in the first channel successively on the time axis.

In addition, FIG. 50 illustrates that transmission slot 5303A fortransmitting to repeater 5200A a modulation signal containing at leastpart of data transmitted by device 5210 or at least part of datarelevant to the transmitted data, and transmission slot 5303C fortransmitting to repeater 5200C a modulation signal containing at leastpart of the data transmitted by device 5210 or at least part of datarelevant to the transmitted data are allocated to repeater 5200B in thesecond channel. Note that, as already described, repeater 5200B has amechanism for obtaining the data transmitted by device 5210.

The first channel and the second channel are channels (frequencydomains) different from each other. Note that, the first channel and thesecond channel may be adjacent to each other or may be separated fromeach other.

Accordingly, when device 5210 is newly connected to repeater 5200B,transmission slots 5303A and 5303C for transmitting modulation signalscontaining at least part of data transmitted by device 5210 or at leastpart of data relevant to the transmitted data can be allocated torepeater 5200B without changing allocation of existing slots to repeater5200B (for example, the allocation of the slots in the first channel).That is, it is possible to omit allocation change of the existing slotswhen a new slot is allocated to a repeater.

In addition, transmission slot 5303A can be allocated such that theperiod of transmission slot 5303A for transmitting to repeater 5200A amodulation signal containing at least part of data transmitted by device5210 or at least part of data relevant to the transmitted data is withinthe period of transmission slot 5301A for transmission also to repeater5200A as illustrated in FIG. 50 .

Similarly, transmission slot 5303C can be allocated such that the periodof transmission slot 5303C for transmitting to repeater 5200C amodulation signal containing at least part of data transmitted by device5210 or at least part of data relevant to the transmitted data is withinthe period of transmission slot 5301C for transmission also to repeater5200C.

Accordingly, repeater 5200B only has to direct the beam directivitytoward repeater 5200A during the period of transmission slot 5301A, anddirect the beam directivity toward repeater 5200C during the period oftransmission slot 5301C. Accordingly, the directivity control of thebeam in repeater 5200B is facilitated. For example, it is possible forrepeater 5200B to use a common precoding matrix for transmission slot5301A and transmission slot 5303A, so that an effect of allowingsimplification of the procedure for beamforming and simplification of atleast part of the signal processing is obtained.

Note that, reception slots 5302C and 5302A illustrated in FIG. 50 arebasically the same as in the case of FIG. 47 and, therefore, thedescriptions thereof are omitted.

FIG. 51 illustrates a variation of slot allocation to repeater 5200B ofFIG. 49 . Note that, likewise in FIG. 50 , the horizontal axisrepresents time and the vertical axis represents the frequency in FIG.51 . In addition, a channel formed in the first frequency band is calleda first channel, and the first channel includes a first carrier groupcomposed of one or more carriers and a second carrier group composed ofone or more carriers.

FIG. 51 illustrates that transmission slot 5401A for transmission torepeater 5200A, transmission slot 5401C for transmission to repeater5200C, reception slot 5402C for reception from repeater 5200C, andreception slot 5402A for reception from repeater 5200C are allocated torepeater 5200B successively on the time axis in the first carrier groupof the first channel.

In addition, FIG. 51 illustrates that transmission slot 5403A fortransmitting to repeater 5200A a modulation signal including at leastpart of data transmitted by device 5210 or at least part of datarelevant to the transmitted data, and transmission slot 5403C fortransmitting to repeater 5200C a modulation signal including at leastpart of data transmitted by device 5210 or at least part of datarelevant to the transmitted data are allocated to repeater 5200B in thesecond carrier group of the first channel. Note that, as alreadydescribed, repeater 5200B holds a mechanism for obtaining the datatransmitted by device 5210.

Each of the first carrier group and the second carrier group includesone or more carriers. The first carrier group and the second carriergroup respectively have frequency domains different from each other. Thenumber of carriers in the first carrier group and the number of carriersin the second carrier group may be the same as each other or differentfrom each other. The first carrier group and the second carrier groupmay be adjacent to each other or may be separated from each other.

Accordingly, when device 5210 is newly connected to repeater 5200B,transmission slots 5403A and 5403C for transmitting modulation signalscontaining at least part of data transmitted by device 5210 or at leastpart of data relevant to the transmitted data can be allocated torepeater 5200B without changing allocation of existing slots to repeater5200B (for example, the allocation of the slots in the first carriergroup). That is, it is possible to omit allocation change of theexisting slots when a new slot is allocated to a repeater.

In addition, an effect of adjustability of the data transmission ratewith slots in the carrier groups is obtained, which is achieved byadjusting the number of carriers constituting the carrier groups. Forexample, when the data amount of the signal from device 5210 is small,the second carrier group may be constituted by a small number ofcarriers, whereas when the data amount of the signal from device 5210 islarge, the second carrier group may be constituted by a large number ofcarriers.

In addition, transmission slot 5403A can be allocated such that theperiod of transmission slot 5403A for transmitting to repeater 5200A amodulation signal containing at least part of data transmitted by device5210 or at least part of data relevant to the transmitted data is withinthe period of transmission slot 5401A for transmission also to repeater5200A as illustrated in FIG. 51 .

Similarly, transmission slot 5403C can be allocated such that the periodof transmission slot 5403C for transmitting to repeater 5200C amodulation signal containing at least part of data transmitted by device5210 or at least part of data relevant to the transmitted data is withinthe period of transmission slot 5401C for transmission also to repeater5200C.

Accordingly, repeater 5200B only has to direct the beam directivitytoward repeater 5200A during the period of transmission slot 5401A, anddirect the beam directivity toward repeater 5200C during the period oftransmission slot 5401C.

Accordingly, the directivity control of the beam in repeater 5200B isfacilitated. For example, it is possible for repeater 5200B to use acommon precoding matrix for transmission slot 5401A and transmissionslot 5403A, so that an effect of allowing simplification of theprocedure for beamforming and simplification of at least part of thesignal processing is obtained.

Note that the basic operation of reception slots 5402C and 5402Aillustrated in FIG. 51 is the same as in the case of FIG. 47 and,therefore, the description thereof is omitted.

FIG. 52 illustrates a variation of connection between repeatersaccording to Embodiment 9.

FIG. 52 differs from FIG. 49 in that device 5211 is connected torepeater 5200A. Similarly to device 5210 in FIG. 49 , device 5211 is animage capturing device for capturing a moving image or a still image(e.g., a surveillance camera), a predetermined sensor, or a radio basestation, for example.

Repeater 5200B also performs the following processing in addition to theprocessing described with reference to FIG. 49 . That is, repeater 5200Areceives data transmitted by device 5211, and transmits to repeater5200B modulation signal 5205A including at least part of the receiveddata or at least part of data relevant to the received data.

Then, repeater 5200B transmits to repeater 5200C modulation signal 5204Cincluding at least part of the data obtained by receiving thismodulation signal 5205A or at least part of data relevant to theobtained data. That is, repeater 5200B relays to repeater 5200C themodulation signal including at least part of the data transmitted bydevice 5211 or at least part of the data relevant to the datatransmitted by device 5211.

FIG. 53 illustrates an example of slot allocation to repeater 5200B ofFIG. 52 .

FIG. 53 differs from FIG. 50 in the second channel in terms of thefollowing points.

Repeater 5200A transmits a modulation signal generated from at leastpart of the data obtained from connected device 5211 or at least part ofthe data relevant to the obtained data. The transmitted modulationsignal is then received by repeater 5200B. The reception slot forrepeater 5200B to receive this modulation signal is reception slot 5305Ain FIG. 53 .

In addition, repeater 5200B transmits to repeater 5200C the dataobtained in last or other previous reception slot 5305A. Thetransmission slot for repeater 5200B to transmit the modulation signalincluding this data is transmission slot 5304C.

Accordingly, when device 5211 is newly connected to repeater 5200A,transmission slot 5304C and reception slot 5305A can be allocated in thesecond channel without changing the allocation of the existing slots inthe first channel to repeater 5200B (for example, the allocation of theslots illustrated in FIG. 50 ). That is, it is possible to obtain aneffect of allowing omission of allocation change of existing slots whena new slot is allocated to a repeater.

Further, as illustrated in FIG. 53 , transmission slot 5304C isallocated such that the period of transmission slot 5304C is within theperiod of transmission slot 5301C for transmission also to repeater5200C and is different from the period of transmission slot 5303C whichhas already been allocated previously.

Thus, repeater 5200B only has to direct the beam directivity towardrepeater 5200C during the period of transmission slot 5301C.Accordingly, the directivity control of the beam in repeater 5200B isfacilitated. For example, it is possible for repeater 5200B to use acommon precoding matrix for transmission slot 5301C, transmission slot5303C, and transmission slot 5304C, so that an effect of allowingsimplification of the procedure for beamforming and simplification of atleast part of the signal processing is obtained.

FIG. 54 illustrates Variation 1 of the slot allocation to repeater 5200Bof FIG. 52 .

FIG. 54 differs from FIG. 51 in the second carrier group of the firstchannel in terms of the following points.

Repeater 5200A transmits a modulation signal generated from at leastpart of data obtained from connected device 5211 or at least part ofdata relevant to the obtained data. Then, repeater 5200B receives themodulation signal transmitted by repeater 5200A. That is, the slot forreception from repeater 5200A is reception slot 5405A in FIG. 54 .

In addition, repeater 5200B transmits the data obtained in receptionslot 5405A to repeater 5200C. The slot for transmitting the modulationsignal including the data to be transmitted to repeater 5200C istransmission slot 5404C.

Accordingly, when device 5211 is newly connected to repeater 5200A,transmission slot 5404C and reception slot 5405A can be allocatedwithout changing the allocation of the existing slots to repeater 5200B(for example, the allocation of the slots illustrated in FIG. 51 ). Thatis, it is possible to obtain an effect of allowing omission ofallocation change of existing slots when a new slot is allocated to arepeater.

Further, as illustrated in FIG. 54 , transmission slot 5404C isallocated such that the period of transmission slot 5404C is within theperiod of transmission slot 5401C for transmission also to repeater5200C and is different from the period of transmission slot 5403C whichhas already been allocated previously.

Thus, repeater 5200B only has to direct the beam directivity towardrepeater 5200C during the period of transmission slot 5401C.Accordingly, the directivity control of the beam in repeater 5200B isfacilitated. For example, it is possible for repeater 5200B to use acommon precoding matrix for transmission slot 5401C, transmission slot5403C, and transmission slot 5404C, so that an effect of allowingsimplification of the procedure for beamforming and simplification of atleast part of the signal processing is obtained.

FIG. 55 illustrates Variation 2 of the slot allocation to repeater 5200Bof FIG. 52 .

FIG. 55 differs from FIG. 50 in the third channel in terms of thefollowing points.

Repeater 5200A transmits a modulation signal generated from at leastpart of data obtained from connected device 5211 or at least part ofdata relevant to the obtained data. The transmitted modulation signal isthen received by repeater 5200B. The slot for reception from repeater5200A is reception slot 5307A in FIG. 55 .

In addition, repeater 5200B transmits the data obtained in receptionslot 5307A to repeater 5200C. The transmission slot for transmitting themodulation signal including the data to be transmitted to repeater 5200Cis transmission slot 5306C.

Accordingly, when device 5211 is newly connected to repeater 5200A,transmission slot 5306C and reception slot 5307A can be allocatedwithout changing the allocation of the existing slots to repeater 5200B(for example, the allocation of the slot illustrated in FIG. 50). Thatis, it is possible to obtain an effect of allowing omission ofallocation change of existing slots when a new slot is allocated to arepeater.

Further, as illustrated in FIG. 55 , transmission slot 5306C isallocated such that the period of transmission slot 5306C is within theperiod of transmission slot 5301C for transmission also to repeater5200C and the channel of transmission slot 5306C is a channel differentfrom those of transmission slots 5301C and 5303C which have already beenallocated previously.

Thus, repeater 5200B only has to direct the beam directivity towardrepeater 5200C during the period of transmission slot 5301C.Accordingly, the directivity control of the beam in repeater 5200B isfacilitated. For example, it is possible for repeater 5200B to use acommon precoding matrix for transmission slot 5301C, transmission slot5303C, and transmission slot 5306C, so that an effect of allowingsimplification of the procedure for beamforming and simplification of atleast part of the signal processing is obtained.

FIG. 56 illustrates Variation 3 of the slot allocation to repeater 5200Bof FIG. 52 .

FIG. 56 differs from FIG. 51 in the third carrier group in terms of thefollowing points.

Repeater 5200A transmits a modulation signal generated from at leastpart of data obtained from connected device 5211 or at least part ofdata relevant to the obtained data. Then, repeater 5200B receives themodulation signal transmitted by repeater 5200A. That is, the slot forreception from repeater 5200A is reception slot 5407A in FIG. 56 .

In addition, repeater 5200B transmits the data obtained in receptionslot 5407A to repeater 5200C. The slot for transmitting the modulationsignal including the data to be transmitted to repeater 5200C istransmission slot 5406C.

Accordingly, when device 5211 is newly connected to repeater 5200A,transmission slot 5406C and reception slot 5407A can be allocatedwithout changing the allocation of the existing slots to repeater 5200B(for example, the allocation of the slots illustrated in FIG. 51). Thatis, it is possible to obtain an effect of allowing omission ofallocation change of existing slots when a new slot is allocated to arepeater.

Further, as illustrated in FIG. 56 , transmission slot 5406C isallocated such that the period of transmission slot 5406C is within theperiod of transmission slot 5401C for transmission also to repeater5200C and the carrier group of transmission slot 5406C is a carriergroup different from those of transmission slots 5401C and 5403C whichhave already been allocated previously.

Thus, repeater 5200B only has to direct the beam directivity towardrepeater 5200C during the period of transmission slot 5401C.Accordingly, the directivity control of the beam in repeater 5200B isfacilitated. For example, it is possible for repeater 5200B to use acommon precoding matrix for transmission slot 5401C, transmission slot5403C, and transmission slot 5406C, so that an effect of allowingsimplification of the procedure for beamforming and simplification of atleast part of the signal processing is obtained.

FIG. 57 illustrates an example of the configuration of a signaltransmitted and received between repeaters.

The signal between the repeaters may have a configuration of a frameaccording to IEEE802.11ad or IEEE802.11ay illustrated in FIG. 57 .

FIG. 57 illustrates an example of the frame configuration whosehorizontal axis represents time. In FIG. 57 , the “BTI” stands forBeacon Transmission Interval. The “A-BFT” stands for AssociationBeamforming Training. The “ATI” stands for Announcement TransmissionInterval. There are “CBAP1” and “CBAP2,” and “CBAP” stands forContention-Based Access Period. The “SP” denotes Scheduled ServicePeriod. The “TDD” stands for Time Division Duplex. The “STA” denotesStation. The “TX” denotes Transmitter, and “RX” denotes Receiver.

In the frame of FIG. 57 , a repeater transmits “BTI,” “A-BFT,” “ATI,”“CBAP1,” “SP1,” “SP with Time Division (TD) channel access,” and “CBAP2”in this order.

The “SP with TD channel access” is composed of “TDD interval 1,” “TDDinterval 2,” . . . , and “TDD interval n.” Note that “n” is an integerequal to or greater than 1. Note also that each of the “TDD intervals”is composed of one or more TDD slots.

For example, the slots described with reference to FIGS. 45 to 56 may becomposed of the TDD-slots illustrated in FIG. 57 . By way ofillustration, the transmission slots may correspond to TDD-slots 0 to 2illustrated in FIG. 57 , and the reception slots may correspond toTDD-slots 3 to 5 illustrated in FIG. 57 . Note that, the frequency axisis not indicated in FIG. 57 .

Note also that, the repeaters described with reference to FIGS. 45 to 56may have the configuration illustrated in FIG. 1 , for example. Forexample, reception-antenna group 151, radio group 153, and signalprocessor 155 serve as a processor (processing circuit) for demodulatingthe reception slots in FIGS. 45 to 56 . In addition, signal processor(signal processing circuit) 102, radios (radio circuits) 104-1 to 104-M,and antennas 106-1 to 106-M perform processing for transmittingmodulation signals in the transmission slots.

Setter (setting circuit) 158 performs scheduling of the transmissionslots and the reception slots, and performs transmission processing ofthe transmission slots and reception processing of the reception slotsproperly.

Note that, a “transmission scheme for transmitting one stream (or onemodulation signal)” or a “transmission scheme for transmitting two ormore streams (or two or more modulation signals)” may be used in thetransmission slots and the reception slots in FIGS. 47, 48, 50, 51, 53,54, 55, and 56 of the present embodiment.

The configuration of the repeaters is not limited to the configurationof FIG. 1 . For example, as for the transmission function and thereception function, the repeaters may be configured to support“transmission and reception of a single stream.” Therefore, radios 104-2to 104-M and antennas 106-2 to 106-M may be omitted, and each of therepeaters may be configured, for example, with radio 104-1 and antenna106-1 in FIG. 1 .

In addition, each of the transmission slots and each of the receptionslots in FIGS. 47, 48, 50, 51, 53, 54, 55, and 56 of the presentembodiment may exist at the same time when the directivity control ofthe transmission beam and the directivity control of the reception beamare performed independently as described in relation to otherembodiments.

The frequency band in which a transmission slot exists and the frequencyband in which a reception slot exists may be arranged in differentfrequency bands, and the channel in which a transmission slot exists andthe channel in which a reception slot exists may be arranged indifferent channels. Further, the carrier group in which a transmissionslot exists and the carrier group in which a reception slot exists maybe arranged in different carrier groups.

As described above, the repeater operates according to the presentembodiment to provide another repeater with data provided by anapparatus other than the repeater, and such relaying of data allowsaddition of a new function. A relaying method performed according to thepresent embodiment provides an effect of allowing omission of allocationchange of existing slots in allocating a new slot.

Variation 1 of Embodiment 9

Although Embodiment 9 has been described in which device 5210 in FIGS.49 and 52 and device 5211 in FIG. 52 may be a radio base station, thosedevices may also be a wired base station using wired communicationinstead of radio communication, or a communication device using a wire.

Supplementary Description

Hereinafter, a supplementary description will be given of thetransmission apparatus, the reception apparatus, the transmissionmethod, and the reception method of the present disclosure.

The transmission apparatus according to one aspect of the presentdisclosure is a transmission apparatus including a plurality oftransmission antennas, the transmission apparatus including: a signalprocessor that modulates data of a first stream to generate a firstbaseband signal, and modulates data of a second stream to generate asecond baseband signal; and a transmission section that generates fromthe first baseband signal a plurality of first transmission signalshaving respective different directivities, generates from the secondbaseband signal a plurality of second transmission signals havingrespective different directivities, and transmits the plurality of firsttransmission signals and the plurality of second transmission signals atthe same time, in which, when receiving a request for transmission ofthe first stream from a terminal, the transmission section furthergenerates from the first baseband signal a plurality of thirdtransmission signals being different from the plurality of firsttransmission signals and having respective different directivities, andtransmits the plurality of third transmission signals.

Each of the plurality of first transmission signals and the plurality ofsecond transmission signals may include a control signal for indicatingwhich one of the data of the first stream and the data of the secondstream is transmitted by the transmission signal.

Each of the plurality of first transmission signals and the plurality ofsecond transmission signals may include a training signal for areception apparatus to perform directivity control.

The reception apparatus according to one aspect of the presentdisclosure is a reception apparatus including a plurality of receptionantennas, the reception apparatus including: a reception section thatselects at least one first signal and at least one second signal among aplurality of first signals and a plurality of second signals transmittedby a transmission apparatus at the same time, the plurality of firstsignals being for transmitting data of a first stream and havingrespective different directivities, the plurality of second signalsbeing for transmitting data of a second stream and having respectivedifferent directivities, and then performs directivity control forreceiving a plurality of selected signals, so as to receive theplurality of selected signals; a signal processor that demodulates thereceived signals and outputs data of the first stream and data of thesecond stream; and a transmission section that requests, from thetransmission apparatus, transmission of the first stream when the atleast one first signal has not been received by the reception section.

The reception section may select the at least one first signal and theat least one second signal based on a control signal for indicatingwhich one of the data of the first stream and the data of the secondstream included in a plurality of reception signals is transmitted bythe signal.

The reception section may perform directivity control using a trainingsignal included in each of the plurality of reception signals.

The transmission method according to one aspect of the presentdisclosure is a transmission method performed by a transmissionapparatus including a plurality of transmission antennas, thetransmission method including: processing of modulating data of a firststream to generate a first baseband signal, and modulating data of asecond stream to generate a second baseband signal; and processing ofgenerating from the first baseband signal a plurality of firsttransmission signals having respective different directivities,generating from the second baseband signal a plurality of secondtransmission signals having respective different directivities, andtransmitting the plurality of first transmission signals and theplurality of second transmission signals at the same time, in which, inthe transmission processing, a plurality of third transmission signalsbeing different from the plurality of first transmission signals andhaving respective different directivities are further generated from thefirst baseband signal and transmitted when a request for transmission ofthe first stream is received from a terminal.

The reception method according to one aspect of the present disclosureis a reception method performed by a reception apparatus including aplurality of reception antennas, the reception method including:processing of selecting at least one first signal and at least onesecond signal among a plurality of first signals and a plurality ofsecond signals transmitted by a transmission apparatus at the same time,the plurality of first signals being for transmitting data of a firststream and having respective different directivities, the plurality ofsecond signals being for transmitting data of a second stream and havingrespective different directivities, and then performing directivitycontrol for receiving a plurality of selected signals, so as to receivethe plurality of selected signals; processing of demodulating thereceived signals and outputting data of the first stream and data of thesecond stream; and processing of requesting, from the transmissionapparatus, transmission of the first stream when the at least one firstsignal has not been received in the reception processing.

The communication apparatus according to one aspect of the presentdisclosure is a communication apparatus that relays a relay signaltransmitted and received between a first communication apparatus and asecond communication apparatus, and that is additionally connected to afirst device, in which the communication apparatus transmits the relaysignal using a first transmission slot, and transmits a signal from thefirst device using a second transmission slot during a transmissionperiod of the first transmission slot in a frequency domain differentfrom a frequency domain of the first transmission slot.

During the period of the first transmission slot, the communicationapparatus according to one aspect of the present disclosure directsdirectivity toward another communication apparatus to which the firsttransmission slot is to be transmitted.

In the communication apparatus according to one aspect of the presentdisclosure, a second device is connected to the first communicationapparatus or the second communication apparatus, and the communicationapparatus transmits a signal using a third transmission slot in afrequency domain different from the frequency domain of the firsttransmission slot and the frequency domain of the second transmissionslot, the signal being a signal received from the second device via acommunication apparatus to which the second device is connected.

In the communication apparatus according to one aspect of the presentdisclosure, a second device is connected to the first communicationapparatus or the second communication apparatus, and the communicationapparatus transmits a signal using a third transmission slot during theperiod of the first transmission slot in a frequency domain common tothe second transmission slot, the signal being a signal received fromthe second device via a communication apparatus to which the seconddevice is connected.

The communication method according to one aspect of the presentdisclosure is a communication method for a communication apparatus thatrelays a relay signal transmitted and received between a firstcommunication apparatus and a second communication apparatus, and thatis additionally connected to a first device, the communication methodincluding: transmitting the relay signal using a first transmissionslot; and transmitting a signal from the first device using a secondtransmission slot during a period of the first transmission slot in afrequency domain different from a frequency domain of the firsttransmission slot.

The present disclosure can be realized by any kind of apparatus, deviceor system having a function of communication, which is referred to as acommunication apparatus. Some non-limiting examples of such acommunication apparatus include a phone (e.g., cellular (cell) phone,smart phone), a tablet, a personal computer (PC) (e.g., laptop, desktop,netbook), a camera (e.g., digital still/video camera), a digital player(digital audio/video player), a wearable device (e.g., wearable camera,smart watch, tracking device), a game console, a digital book reader, atelehealth/telemedicine (remote health and medicine) device, and avehicle providing communication functionality (e.g., automotive,airplane, ship), and various combinations thereof.

The communication apparatus is not limited to be portable or movable,and may also include any kind of apparatus, device or system beingnon-portable or stationary, such as a smart home device (e.g., anappliance, lighting, smart meter, control panel), a vending machine, andany other “things” in a network of an “Internet of Things (IoT).”

The communication may include exchanging data through, for example, acellular system, a radio LAN system, a satellite system, etc., andvarious combinations thereof.

The communication apparatus may comprise a device such as a controlleror a sensor which is coupled to a communication device performing afunction of communication described in the present disclosure. Forexample, the communication apparatus may comprise a controller or asensor that generates control signals or data signals which are used bya communication device performing a communication function of thecommunication apparatus.

The communication apparatus also may include an infrastructure facility,such as a base station, an access point, and any other apparatus, deviceor system that communicates with or controls apparatuses such as thosein the above non-limiting examples.

According to the present disclosure, there is a possibility of achievinga greater communication distance in multicast/broadcast communicationwith a plurality of streams than in the case where an antenna of aquasi-omni pattern is used.

INDUSTRIAL APPLICABILITY

The present disclosure is useful in communication using a plurality ofantennas.

REFERENCE SIGNS LIST

-   -   700 Base station    -   701 Antenna    -   702, 703 Transmission beam    -   704 Terminal    -   705, 706 Reception directivity

The invention claimed is:
 1. A relay apparatus comprising: a receiverwhich, in operation, receives a first relay signal from a first relayapparatus and receives a first data signal from a first device; and atransmitter which, in operation, transmits the first relay signal andthe first data signal to a second relay apparatus by using a firsttransmission slot and a second transmission slot, respectively, whereinthe first transmission slot is located within a first time period over afirst frequency band and the second transmission slot is located withinthe first time period over a second frequency band different from thefirst frequency band.
 2. The relay apparatus according to claim 1,wherein the transmission of the first relay signal and the transmissionof the first data signal are performed by using a single transmissionbeam directed to the second relay apparatus.
 3. The relay apparatusaccording to claim 1, wherein the receiver, in operation, receives asecond data signal from a second device that is physically or wirelesslyconnected to the first relay apparatus; and the transmitter, inoperation, transmits the second data signal to the second relayapparatus by using a third transmission slot located within the firsttime period over a third frequency band different from the firstfrequency band.
 4. The relay apparatus according to claim 3, wherein thethird frequency band is different from the second frequency band.
 5. Therelay apparatus according to claim 3, wherein the transmission of thesecond data signal, the transmission of the first relay signal, and thetransmission of the first data signal are performed by using a singletransmission beam directed to the second relay apparatus.
 6. The relayapparatus according to claim 1, wherein the receiver, in operation,receives a second relay signal from the second relay apparatus andreceives a second data signal from the first device; the transmitter, inoperation, transmits the second relay signal and the second data signalto the first relay apparatus by using a fourth transmission slot and afifth transmission slot, respectively, wherein the fourth transmissionslot is located within a second time period over the first frequencyband and the fifth transmission slot is located within the second timeperiod over the second frequency band.
 7. The relay apparatus accordingto claim 6, wherein the transmission of the second relay signal and thetransmission of the second data signal are performed by using a singletransmission beam directed to the first relay apparatus.
 8. The relayapparatus according to claim 6, wherein a first transmission beam usedfor the transmission to the first relay apparatus is different from asecond transmission beam used for the transmission to the second relayapparatus.
 9. A communication method for a relay apparatus, thecommunication method comprising: receiving a first relay signal from afirst relay apparatus; receiving a first data signal from a firstdevice; and transmitting the first relay signal and the first datasignal to a second relay apparatus by using a first transmission slotand a second transmission slot, respectively, wherein the firsttransmission slot is located within a first time period over a firstfrequency band and the second transmission slot is located within thefirst time period over a second frequency band different from the firstfrequency band.
 10. The communication method according to claim 9,wherein the transmission of the first relay signal and the transmissionof the first data signal are performed by using a single transmissionbeam directed to the second relay apparatus.
 11. The communicationmethod according to claim 9, comprising: receiving a second data signalfrom a second device that is physically or wirelessly connected to thefirst relay apparatus; and transmitting the second data signal to thesecond relay apparatus by using a third transmission slot located withinthe first time period over a third frequency band different from thefirst frequency band.
 12. The communication method according to claim11, wherein the third frequency band is different from the secondfrequency band.
 13. The communication method according to claim 11,wherein the transmission of the second data signal, the transmission ofthe first relay signal, and the transmission of the first data signalare performed by using a single transmission beam directed to the secondrelay apparatus.
 14. The communication method according to claim 9,comprising: receiving a second relay signal from the second relayapparatus and receiving a second data signal from the first device;transmitting the second relay signal and the second data signal to thefirst relay apparatus by using a fourth transmission slot and a fifthtransmission slot, respectively, wherein the fourth transmission slot islocated within a second time period over the first frequency band andthe fifth transmission slot is located within the second time periodover the second frequency band.
 15. The communication method accordingto claim 14, wherein the transmission of the second relay signal and thetransmission of the second data signal are performed by using a singletransmission beam directed to the first relay apparatus.
 16. Thecommunication method according to claim 14, wherein a first transmissionbeam used for the transmission to the first relay apparatus is differentfrom a second transmission beam used for the transmission to the secondrelay apparatus.